Added query/connection expectation support to TransactionProfiler
[lhc/web/wiklou.git] / includes / db / Database.php
1 <?php
2
3 /**
4 * @defgroup Database Database
5 *
6 * This file deals with database interface functions
7 * and query specifics/optimisations.
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
22 * http://www.gnu.org/copyleft/gpl.html
23 *
24 * @file
25 * @ingroup Database
26 */
27
28 /**
29 * Interface for classes that implement or wrap DatabaseBase
30 * @ingroup Database
31 */
32 interface IDatabase {
33 }
34
35 /**
36 * Database abstraction object
37 * @ingroup Database
38 */
39 abstract class DatabaseBase implements IDatabase {
40 /** Number of times to re-try an operation in case of deadlock */
41 const DEADLOCK_TRIES = 4;
42
43 /** Minimum time to wait before retry, in microseconds */
44 const DEADLOCK_DELAY_MIN = 500000;
45
46 /** Maximum time to wait before retry */
47 const DEADLOCK_DELAY_MAX = 1500000;
48
49 protected $mLastQuery = '';
50 protected $mDoneWrites = false;
51 protected $mPHPError = false;
52
53 protected $mServer, $mUser, $mPassword, $mDBname;
54
55 /** @var resource Database connection */
56 protected $mConn = null;
57 protected $mOpened = false;
58
59 /** @var callable[] */
60 protected $mTrxIdleCallbacks = array();
61 /** @var callable[] */
62 protected $mTrxPreCommitCallbacks = array();
63
64 protected $mTablePrefix;
65 protected $mSchema;
66 protected $mFlags;
67 protected $mForeign;
68 protected $mErrorCount = 0;
69 protected $mLBInfo = array();
70 protected $mDefaultBigSelects = null;
71 protected $mSchemaVars = false;
72
73 protected $preparedArgs;
74
75 protected $htmlErrors;
76
77 protected $delimiter = ';';
78
79 /**
80 * Either 1 if a transaction is active or 0 otherwise.
81 * The other Trx fields may not be meaningfull if this is 0.
82 *
83 * @var int
84 */
85 protected $mTrxLevel = 0;
86
87 /**
88 * Either a short hexidecimal string if a transaction is active or ""
89 *
90 * @var string
91 * @see DatabaseBase::mTrxLevel
92 */
93 protected $mTrxShortId = '';
94
95 /**
96 * The UNIX time that the transaction started. Callers can assume that if
97 * snapshot isolation is used, then the data is *at least* up to date to that
98 * point (possibly more up-to-date since the first SELECT defines the snapshot).
99 *
100 * @var float|null
101 * @see DatabaseBase::mTrxLevel
102 */
103 private $mTrxTimestamp = null;
104
105 /**
106 * Remembers the function name given for starting the most recent transaction via begin().
107 * Used to provide additional context for error reporting.
108 *
109 * @var string
110 * @see DatabaseBase::mTrxLevel
111 */
112 private $mTrxFname = null;
113
114 /**
115 * Record if possible write queries were done in the last transaction started
116 *
117 * @var bool
118 * @see DatabaseBase::mTrxLevel
119 */
120 private $mTrxDoneWrites = false;
121
122 /**
123 * Record if the current transaction was started implicitly due to DBO_TRX being set.
124 *
125 * @var bool
126 * @see DatabaseBase::mTrxLevel
127 */
128 private $mTrxAutomatic = false;
129
130 /**
131 * Array of levels of atomicity within transactions
132 *
133 * @var SplStack
134 */
135 private $mTrxAtomicLevels;
136
137 /**
138 * Record if the current transaction was started implicitly by DatabaseBase::startAtomic
139 *
140 * @var bool
141 */
142 private $mTrxAutomaticAtomic = false;
143
144 /**
145 * @since 1.21
146 * @var resource File handle for upgrade
147 */
148 protected $fileHandle = null;
149
150 /**
151 * @since 1.22
152 * @var string[] Process cache of VIEWs names in the database
153 */
154 protected $allViews = null;
155
156 /**
157 * A string describing the current software version, and possibly
158 * other details in a user-friendly way. Will be listed on Special:Version, etc.
159 * Use getServerVersion() to get machine-friendly information.
160 *
161 * @return string Version information from the database server
162 */
163 public function getServerInfo() {
164 return $this->getServerVersion();
165 }
166
167 /**
168 * @return string Command delimiter used by this database engine
169 */
170 public function getDelimiter() {
171 return $this->delimiter;
172 }
173
174 /**
175 * Boolean, controls output of large amounts of debug information.
176 * @param bool|null $debug
177 * - true to enable debugging
178 * - false to disable debugging
179 * - omitted or null to do nothing
180 *
181 * @return bool|null Previous value of the flag
182 */
183 public function debug( $debug = null ) {
184 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
185 }
186
187 /**
188 * Turns buffering of SQL result sets on (true) or off (false). Default is
189 * "on".
190 *
191 * Unbuffered queries are very troublesome in MySQL:
192 *
193 * - If another query is executed while the first query is being read
194 * out, the first query is killed. This means you can't call normal
195 * MediaWiki functions while you are reading an unbuffered query result
196 * from a normal wfGetDB() connection.
197 *
198 * - Unbuffered queries cause the MySQL server to use large amounts of
199 * memory and to hold broad locks which block other queries.
200 *
201 * If you want to limit client-side memory, it's almost always better to
202 * split up queries into batches using a LIMIT clause than to switch off
203 * buffering.
204 *
205 * @param null|bool $buffer
206 * @return null|bool The previous value of the flag
207 */
208 public function bufferResults( $buffer = null ) {
209 if ( is_null( $buffer ) ) {
210 return !(bool)( $this->mFlags & DBO_NOBUFFER );
211 } else {
212 return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
213 }
214 }
215
216 /**
217 * Turns on (false) or off (true) the automatic generation and sending
218 * of a "we're sorry, but there has been a database error" page on
219 * database errors. Default is on (false). When turned off, the
220 * code should use lastErrno() and lastError() to handle the
221 * situation as appropriate.
222 *
223 * Do not use this function outside of the Database classes.
224 *
225 * @param null|bool $ignoreErrors
226 * @return bool The previous value of the flag.
227 */
228 public function ignoreErrors( $ignoreErrors = null ) {
229 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
230 }
231
232 /**
233 * Gets the current transaction level.
234 *
235 * Historically, transactions were allowed to be "nested". This is no
236 * longer supported, so this function really only returns a boolean.
237 *
238 * @return int The previous value
239 */
240 public function trxLevel() {
241 return $this->mTrxLevel;
242 }
243
244 /**
245 * Get the UNIX timestamp of the time that the transaction was established
246 *
247 * This can be used to reason about the staleness of SELECT data
248 * in REPEATABLE-READ transaction isolation level.
249 *
250 * @return float|null Returns null if there is not active transaction
251 * @since 1.25
252 */
253 public function trxTimestamp() {
254 return $this->mTrxLevel ? $this->mTrxTimestamp : null;
255 }
256
257 /**
258 * Get/set the number of errors logged. Only useful when errors are ignored
259 * @param int $count The count to set, or omitted to leave it unchanged.
260 * @return int The error count
261 */
262 public function errorCount( $count = null ) {
263 return wfSetVar( $this->mErrorCount, $count );
264 }
265
266 /**
267 * Get/set the table prefix.
268 * @param string $prefix The table prefix to set, or omitted to leave it unchanged.
269 * @return string The previous table prefix.
270 */
271 public function tablePrefix( $prefix = null ) {
272 return wfSetVar( $this->mTablePrefix, $prefix );
273 }
274
275 /**
276 * Get/set the db schema.
277 * @param string $schema The database schema to set, or omitted to leave it unchanged.
278 * @return string The previous db schema.
279 */
280 public function dbSchema( $schema = null ) {
281 return wfSetVar( $this->mSchema, $schema );
282 }
283
284 /**
285 * Set the filehandle to copy write statements to.
286 *
287 * @param resource $fh File handle
288 */
289 public function setFileHandle( $fh ) {
290 $this->fileHandle = $fh;
291 }
292
293 /**
294 * Get properties passed down from the server info array of the load
295 * balancer.
296 *
297 * @param string $name The entry of the info array to get, or null to get the
298 * whole array
299 *
300 * @return array|mixed|null
301 */
302 public function getLBInfo( $name = null ) {
303 if ( is_null( $name ) ) {
304 return $this->mLBInfo;
305 } else {
306 if ( array_key_exists( $name, $this->mLBInfo ) ) {
307 return $this->mLBInfo[$name];
308 } else {
309 return null;
310 }
311 }
312 }
313
314 /**
315 * Set the LB info array, or a member of it. If called with one parameter,
316 * the LB info array is set to that parameter. If it is called with two
317 * parameters, the member with the given name is set to the given value.
318 *
319 * @param string $name
320 * @param array $value
321 */
322 public function setLBInfo( $name, $value = null ) {
323 if ( is_null( $value ) ) {
324 $this->mLBInfo = $name;
325 } else {
326 $this->mLBInfo[$name] = $value;
327 }
328 }
329
330 /**
331 * Set lag time in seconds for a fake slave
332 *
333 * @param mixed $lag Valid values for this parameter are determined by the
334 * subclass, but should be a PHP scalar or array that would be sensible
335 * as part of $wgLBFactoryConf.
336 */
337 public function setFakeSlaveLag( $lag ) {
338 }
339
340 /**
341 * Make this connection a fake master
342 *
343 * @param bool $enabled
344 */
345 public function setFakeMaster( $enabled = true ) {
346 }
347
348 /**
349 * Returns true if this database supports (and uses) cascading deletes
350 *
351 * @return bool
352 */
353 public function cascadingDeletes() {
354 return false;
355 }
356
357 /**
358 * Returns true if this database supports (and uses) triggers (e.g. on the page table)
359 *
360 * @return bool
361 */
362 public function cleanupTriggers() {
363 return false;
364 }
365
366 /**
367 * Returns true if this database is strict about what can be put into an IP field.
368 * Specifically, it uses a NULL value instead of an empty string.
369 *
370 * @return bool
371 */
372 public function strictIPs() {
373 return false;
374 }
375
376 /**
377 * Returns true if this database uses timestamps rather than integers
378 *
379 * @return bool
380 */
381 public function realTimestamps() {
382 return false;
383 }
384
385 /**
386 * Returns true if this database does an implicit sort when doing GROUP BY
387 *
388 * @return bool
389 */
390 public function implicitGroupby() {
391 return true;
392 }
393
394 /**
395 * Returns true if this database does an implicit order by when the column has an index
396 * For example: SELECT page_title FROM page LIMIT 1
397 *
398 * @return bool
399 */
400 public function implicitOrderby() {
401 return true;
402 }
403
404 /**
405 * Returns true if this database can do a native search on IP columns
406 * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
407 *
408 * @return bool
409 */
410 public function searchableIPs() {
411 return false;
412 }
413
414 /**
415 * Returns true if this database can use functional indexes
416 *
417 * @return bool
418 */
419 public function functionalIndexes() {
420 return false;
421 }
422
423 /**
424 * Return the last query that went through DatabaseBase::query()
425 * @return string
426 */
427 public function lastQuery() {
428 return $this->mLastQuery;
429 }
430
431 /**
432 * Returns true if the connection may have been used for write queries.
433 * Should return true if unsure.
434 *
435 * @return bool
436 */
437 public function doneWrites() {
438 return (bool)$this->mDoneWrites;
439 }
440
441 /**
442 * Returns the last time the connection may have been used for write queries.
443 * Should return a timestamp if unsure.
444 *
445 * @return int|float UNIX timestamp or false
446 * @since 1.24
447 */
448 public function lastDoneWrites() {
449 return $this->mDoneWrites ?: false;
450 }
451
452 /**
453 * Returns true if there is a transaction open with possible write
454 * queries or transaction pre-commit/idle callbacks waiting on it to finish.
455 *
456 * @return bool
457 */
458 public function writesOrCallbacksPending() {
459 return $this->mTrxLevel && (
460 $this->mTrxDoneWrites || $this->mTrxIdleCallbacks || $this->mTrxPreCommitCallbacks
461 );
462 }
463
464 /**
465 * Is a connection to the database open?
466 * @return bool
467 */
468 public function isOpen() {
469 return $this->mOpened;
470 }
471
472 /**
473 * Set a flag for this connection
474 *
475 * @param int $flag DBO_* constants from Defines.php:
476 * - DBO_DEBUG: output some debug info (same as debug())
477 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
478 * - DBO_TRX: automatically start transactions
479 * - DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode
480 * and removes it in command line mode
481 * - DBO_PERSISTENT: use persistant database connection
482 */
483 public function setFlag( $flag ) {
484 global $wgDebugDBTransactions;
485 $this->mFlags |= $flag;
486 if ( ( $flag & DBO_TRX ) && $wgDebugDBTransactions ) {
487 wfDebug( "Implicit transactions are now enabled.\n" );
488 }
489 }
490
491 /**
492 * Clear a flag for this connection
493 *
494 * @param int $flag DBO_* constants from Defines.php:
495 * - DBO_DEBUG: output some debug info (same as debug())
496 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
497 * - DBO_TRX: automatically start transactions
498 * - DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode
499 * and removes it in command line mode
500 * - DBO_PERSISTENT: use persistant database connection
501 */
502 public function clearFlag( $flag ) {
503 global $wgDebugDBTransactions;
504 $this->mFlags &= ~$flag;
505 if ( ( $flag & DBO_TRX ) && $wgDebugDBTransactions ) {
506 wfDebug( "Implicit transactions are now disabled.\n" );
507 }
508 }
509
510 /**
511 * Returns a boolean whether the flag $flag is set for this connection
512 *
513 * @param int $flag DBO_* constants from Defines.php:
514 * - DBO_DEBUG: output some debug info (same as debug())
515 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
516 * - DBO_TRX: automatically start transactions
517 * - DBO_PERSISTENT: use persistant database connection
518 * @return bool
519 */
520 public function getFlag( $flag ) {
521 return !!( $this->mFlags & $flag );
522 }
523
524 /**
525 * General read-only accessor
526 *
527 * @param string $name
528 * @return string
529 */
530 public function getProperty( $name ) {
531 return $this->$name;
532 }
533
534 /**
535 * @return string
536 */
537 public function getWikiID() {
538 if ( $this->mTablePrefix ) {
539 return "{$this->mDBname}-{$this->mTablePrefix}";
540 } else {
541 return $this->mDBname;
542 }
543 }
544
545 /**
546 * Return a path to the DBMS-specific SQL file if it exists,
547 * otherwise default SQL file
548 *
549 * @param string $filename
550 * @return string
551 */
552 private function getSqlFilePath( $filename ) {
553 global $IP;
554 $dbmsSpecificFilePath = "$IP/maintenance/" . $this->getType() . "/$filename";
555 if ( file_exists( $dbmsSpecificFilePath ) ) {
556 return $dbmsSpecificFilePath;
557 } else {
558 return "$IP/maintenance/$filename";
559 }
560 }
561
562 /**
563 * Return a path to the DBMS-specific schema file,
564 * otherwise default to tables.sql
565 *
566 * @return string
567 */
568 public function getSchemaPath() {
569 return $this->getSqlFilePath( 'tables.sql' );
570 }
571
572 /**
573 * Return a path to the DBMS-specific update key file,
574 * otherwise default to update-keys.sql
575 *
576 * @return string
577 */
578 public function getUpdateKeysPath() {
579 return $this->getSqlFilePath( 'update-keys.sql' );
580 }
581
582 /**
583 * Get the type of the DBMS, as it appears in $wgDBtype.
584 *
585 * @return string
586 */
587 abstract function getType();
588
589 /**
590 * Open a connection to the database. Usually aborts on failure
591 *
592 * @param string $server Database server host
593 * @param string $user Database user name
594 * @param string $password Database user password
595 * @param string $dbName Database name
596 * @return bool
597 * @throws DBConnectionError
598 */
599 abstract function open( $server, $user, $password, $dbName );
600
601 /**
602 * Fetch the next row from the given result object, in object form.
603 * Fields can be retrieved with $row->fieldname, with fields acting like
604 * member variables.
605 * If no more rows are available, false is returned.
606 *
607 * @param ResultWrapper|stdClass $res Object as returned from DatabaseBase::query(), etc.
608 * @return stdClass|bool
609 * @throws DBUnexpectedError Thrown if the database returns an error
610 */
611 abstract function fetchObject( $res );
612
613 /**
614 * Fetch the next row from the given result object, in associative array
615 * form. Fields are retrieved with $row['fieldname'].
616 * If no more rows are available, false is returned.
617 *
618 * @param ResultWrapper $res Result object as returned from DatabaseBase::query(), etc.
619 * @return array|bool
620 * @throws DBUnexpectedError Thrown if the database returns an error
621 */
622 abstract function fetchRow( $res );
623
624 /**
625 * Get the number of rows in a result object
626 *
627 * @param mixed $res A SQL result
628 * @return int
629 */
630 abstract function numRows( $res );
631
632 /**
633 * Get the number of fields in a result object
634 * @see http://www.php.net/mysql_num_fields
635 *
636 * @param mixed $res A SQL result
637 * @return int
638 */
639 abstract function numFields( $res );
640
641 /**
642 * Get a field name in a result object
643 * @see http://www.php.net/mysql_field_name
644 *
645 * @param mixed $res A SQL result
646 * @param int $n
647 * @return string
648 */
649 abstract function fieldName( $res, $n );
650
651 /**
652 * Get the inserted value of an auto-increment row
653 *
654 * The value inserted should be fetched from nextSequenceValue()
655 *
656 * Example:
657 * $id = $dbw->nextSequenceValue( 'page_page_id_seq' );
658 * $dbw->insert( 'page', array( 'page_id' => $id ) );
659 * $id = $dbw->insertId();
660 *
661 * @return int
662 */
663 abstract function insertId();
664
665 /**
666 * Change the position of the cursor in a result object
667 * @see http://www.php.net/mysql_data_seek
668 *
669 * @param mixed $res A SQL result
670 * @param int $row
671 */
672 abstract function dataSeek( $res, $row );
673
674 /**
675 * Get the last error number
676 * @see http://www.php.net/mysql_errno
677 *
678 * @return int
679 */
680 abstract function lastErrno();
681
682 /**
683 * Get a description of the last error
684 * @see http://www.php.net/mysql_error
685 *
686 * @return string
687 */
688 abstract function lastError();
689
690 /**
691 * mysql_fetch_field() wrapper
692 * Returns false if the field doesn't exist
693 *
694 * @param string $table Table name
695 * @param string $field Field name
696 *
697 * @return Field
698 */
699 abstract function fieldInfo( $table, $field );
700
701 /**
702 * Get information about an index into an object
703 * @param string $table Table name
704 * @param string $index Index name
705 * @param string $fname Calling function name
706 * @return mixed Database-specific index description class or false if the index does not exist
707 */
708 abstract function indexInfo( $table, $index, $fname = __METHOD__ );
709
710 /**
711 * Get the number of rows affected by the last write query
712 * @see http://www.php.net/mysql_affected_rows
713 *
714 * @return int
715 */
716 abstract function affectedRows();
717
718 /**
719 * Wrapper for addslashes()
720 *
721 * @param string $s String to be slashed.
722 * @return string Slashed string.
723 */
724 abstract function strencode( $s );
725
726 /**
727 * Returns a wikitext link to the DB's website, e.g.,
728 * return "[http://www.mysql.com/ MySQL]";
729 * Should at least contain plain text, if for some reason
730 * your database has no website.
731 *
732 * @return string Wikitext of a link to the server software's web site
733 */
734 abstract function getSoftwareLink();
735
736 /**
737 * A string describing the current software version, like from
738 * mysql_get_server_info().
739 *
740 * @return string Version information from the database server.
741 */
742 abstract function getServerVersion();
743
744 /**
745 * Constructor.
746 *
747 * FIXME: It is possible to construct a Database object with no associated
748 * connection object, by specifying no parameters to __construct(). This
749 * feature is deprecated and should be removed.
750 *
751 * DatabaseBase subclasses should not be constructed directly in external
752 * code. DatabaseBase::factory() should be used instead.
753 *
754 * @param array $params Parameters passed from DatabaseBase::factory()
755 */
756 function __construct( $params = null ) {
757 global $wgDBprefix, $wgDBmwschema, $wgCommandLineMode, $wgDebugDBTransactions;
758
759 $this->mTrxAtomicLevels = new SplStack;
760
761 if ( is_array( $params ) ) { // MW 1.22
762 $server = $params['host'];
763 $user = $params['user'];
764 $password = $params['password'];
765 $dbName = $params['dbname'];
766 $flags = $params['flags'];
767 $tablePrefix = $params['tablePrefix'];
768 $schema = $params['schema'];
769 $foreign = $params['foreign'];
770 } else { // legacy calling pattern
771 wfDeprecated( __METHOD__ . " method called without parameter array.", "1.23" );
772 $args = func_get_args();
773 $server = isset( $args[0] ) ? $args[0] : false;
774 $user = isset( $args[1] ) ? $args[1] : false;
775 $password = isset( $args[2] ) ? $args[2] : false;
776 $dbName = isset( $args[3] ) ? $args[3] : false;
777 $flags = isset( $args[4] ) ? $args[4] : 0;
778 $tablePrefix = isset( $args[5] ) ? $args[5] : 'get from global';
779 $schema = 'get from global';
780 $foreign = isset( $args[6] ) ? $args[6] : false;
781 }
782
783 $this->mFlags = $flags;
784 if ( $this->mFlags & DBO_DEFAULT ) {
785 if ( $wgCommandLineMode ) {
786 $this->mFlags &= ~DBO_TRX;
787 if ( $wgDebugDBTransactions ) {
788 wfDebug( "Implicit transaction open disabled.\n" );
789 }
790 } else {
791 $this->mFlags |= DBO_TRX;
792 if ( $wgDebugDBTransactions ) {
793 wfDebug( "Implicit transaction open enabled.\n" );
794 }
795 }
796 }
797
798 /** Get the default table prefix*/
799 if ( $tablePrefix == 'get from global' ) {
800 $this->mTablePrefix = $wgDBprefix;
801 } else {
802 $this->mTablePrefix = $tablePrefix;
803 }
804
805 /** Get the database schema*/
806 if ( $schema == 'get from global' ) {
807 $this->mSchema = $wgDBmwschema;
808 } else {
809 $this->mSchema = $schema;
810 }
811
812 $this->mForeign = $foreign;
813
814 if ( $user ) {
815 $this->open( $server, $user, $password, $dbName );
816 }
817
818 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
819 $trxProf = Profiler::instance()->getTransactionProfiler();
820 $trxProf->recordConnection( $this->mServer, $this->mDBname, $isMaster );
821 }
822
823 /**
824 * Called by serialize. Throw an exception when DB connection is serialized.
825 * This causes problems on some database engines because the connection is
826 * not restored on unserialize.
827 */
828 public function __sleep() {
829 throw new MWException( 'Database serialization may cause problems, since ' .
830 'the connection is not restored on wakeup.' );
831 }
832
833 /**
834 * Given a DB type, construct the name of the appropriate child class of
835 * DatabaseBase. This is designed to replace all of the manual stuff like:
836 * $class = 'Database' . ucfirst( strtolower( $dbType ) );
837 * as well as validate against the canonical list of DB types we have
838 *
839 * This factory function is mostly useful for when you need to connect to a
840 * database other than the MediaWiki default (such as for external auth,
841 * an extension, et cetera). Do not use this to connect to the MediaWiki
842 * database. Example uses in core:
843 * @see LoadBalancer::reallyOpenConnection()
844 * @see ForeignDBRepo::getMasterDB()
845 * @see WebInstallerDBConnect::execute()
846 *
847 * @since 1.18
848 *
849 * @param string $dbType A possible DB type
850 * @param array $p An array of options to pass to the constructor.
851 * Valid options are: host, user, password, dbname, flags, tablePrefix, schema, driver
852 * @throws MWException If the database driver or extension cannot be found
853 * @return DatabaseBase|null DatabaseBase subclass or null
854 */
855 final public static function factory( $dbType, $p = array() ) {
856 $canonicalDBTypes = array(
857 'mysql' => array( 'mysqli', 'mysql' ),
858 'postgres' => array(),
859 'sqlite' => array(),
860 'oracle' => array(),
861 'mssql' => array(),
862 );
863
864 $driver = false;
865 $dbType = strtolower( $dbType );
866 if ( isset( $canonicalDBTypes[$dbType] ) && $canonicalDBTypes[$dbType] ) {
867 $possibleDrivers = $canonicalDBTypes[$dbType];
868 if ( !empty( $p['driver'] ) ) {
869 if ( in_array( $p['driver'], $possibleDrivers ) ) {
870 $driver = $p['driver'];
871 } else {
872 throw new MWException( __METHOD__ .
873 " cannot construct Database with type '$dbType' and driver '{$p['driver']}'" );
874 }
875 } else {
876 foreach ( $possibleDrivers as $posDriver ) {
877 if ( extension_loaded( $posDriver ) ) {
878 $driver = $posDriver;
879 break;
880 }
881 }
882 }
883 } else {
884 $driver = $dbType;
885 }
886 if ( $driver === false ) {
887 throw new MWException( __METHOD__ .
888 " no viable database extension found for type '$dbType'" );
889 }
890
891 // Determine schema defaults. Currently Microsoft SQL Server uses $wgDBmwschema,
892 // and everything else doesn't use a schema (e.g. null)
893 // Although postgres and oracle support schemas, we don't use them (yet)
894 // to maintain backwards compatibility
895 $defaultSchemas = array(
896 'mysql' => null,
897 'postgres' => null,
898 'sqlite' => null,
899 'oracle' => null,
900 'mssql' => 'get from global',
901 );
902
903 $class = 'Database' . ucfirst( $driver );
904 if ( class_exists( $class ) && is_subclass_of( $class, 'DatabaseBase' ) ) {
905 $params = array(
906 'host' => isset( $p['host'] ) ? $p['host'] : false,
907 'user' => isset( $p['user'] ) ? $p['user'] : false,
908 'password' => isset( $p['password'] ) ? $p['password'] : false,
909 'dbname' => isset( $p['dbname'] ) ? $p['dbname'] : false,
910 'flags' => isset( $p['flags'] ) ? $p['flags'] : 0,
911 'tablePrefix' => isset( $p['tablePrefix'] ) ? $p['tablePrefix'] : 'get from global',
912 'schema' => isset( $p['schema'] ) ? $p['schema'] : $defaultSchemas[$dbType],
913 'foreign' => isset( $p['foreign'] ) ? $p['foreign'] : false
914 );
915
916 return new $class( $params );
917 } else {
918 return null;
919 }
920 }
921
922 protected function installErrorHandler() {
923 $this->mPHPError = false;
924 $this->htmlErrors = ini_set( 'html_errors', '0' );
925 set_error_handler( array( $this, 'connectionErrorHandler' ) );
926 }
927
928 /**
929 * @return bool|string
930 */
931 protected function restoreErrorHandler() {
932 restore_error_handler();
933 if ( $this->htmlErrors !== false ) {
934 ini_set( 'html_errors', $this->htmlErrors );
935 }
936 if ( $this->mPHPError ) {
937 $error = preg_replace( '!\[<a.*</a>\]!', '', $this->mPHPError );
938 $error = preg_replace( '!^.*?:\s?(.*)$!', '$1', $error );
939
940 return $error;
941 } else {
942 return false;
943 }
944 }
945
946 /**
947 * @param int $errno
948 * @param string $errstr
949 */
950 public function connectionErrorHandler( $errno, $errstr ) {
951 $this->mPHPError = $errstr;
952 }
953
954 /**
955 * Create a log context to pass to wfLogDBError or other logging functions.
956 *
957 * @param array $extras Additional data to add to context
958 * @return array
959 */
960 protected function getLogContext( array $extras = array() ) {
961 return array_merge(
962 array(
963 'db_server' => $this->mServer,
964 'db_name' => $this->mDBname,
965 'db_user' => $this->mUser,
966 ),
967 $extras
968 );
969 }
970
971 /**
972 * Closes a database connection.
973 * if it is open : commits any open transactions
974 *
975 * @throws MWException
976 * @return bool Operation success. true if already closed.
977 */
978 public function close() {
979 if ( count( $this->mTrxIdleCallbacks ) ) { // sanity
980 throw new MWException( "Transaction idle callbacks still pending." );
981 }
982 if ( $this->mConn ) {
983 if ( $this->trxLevel() ) {
984 if ( !$this->mTrxAutomatic ) {
985 wfWarn( "Transaction still in progress (from {$this->mTrxFname}), " .
986 " performing implicit commit before closing connection!" );
987 }
988
989 $this->commit( __METHOD__, 'flush' );
990 }
991
992 $closed = $this->closeConnection();
993 $this->mConn = false;
994 } else {
995 $closed = true;
996 }
997 $this->mOpened = false;
998
999 return $closed;
1000 }
1001
1002 /**
1003 * Closes underlying database connection
1004 * @since 1.20
1005 * @return bool Whether connection was closed successfully
1006 */
1007 abstract protected function closeConnection();
1008
1009 /**
1010 * @param string $error Fallback error message, used if none is given by DB
1011 * @throws DBConnectionError
1012 */
1013 function reportConnectionError( $error = 'Unknown error' ) {
1014 $myError = $this->lastError();
1015 if ( $myError ) {
1016 $error = $myError;
1017 }
1018
1019 # New method
1020 throw new DBConnectionError( $this, $error );
1021 }
1022
1023 /**
1024 * The DBMS-dependent part of query()
1025 *
1026 * @param string $sql SQL query.
1027 * @return ResultWrapper|bool Result object to feed to fetchObject,
1028 * fetchRow, ...; or false on failure
1029 */
1030 abstract protected function doQuery( $sql );
1031
1032 /**
1033 * Determine whether a query writes to the DB.
1034 * Should return true if unsure.
1035 *
1036 * @param string $sql
1037 * @return bool
1038 */
1039 public function isWriteQuery( $sql ) {
1040 return !preg_match( '/^(?:SELECT|BEGIN|ROLLBACK|COMMIT|SET|SHOW|EXPLAIN|\(SELECT)\b/i', $sql );
1041 }
1042
1043 /**
1044 * Determine whether a SQL statement is sensitive to isolation level.
1045 * A SQL statement is considered transactable if its result could vary
1046 * depending on the transaction isolation level. Operational commands
1047 * such as 'SET' and 'SHOW' are not considered to be transactable.
1048 *
1049 * @param string $sql
1050 * @return bool
1051 */
1052 public function isTransactableQuery( $sql ) {
1053 $verb = substr( $sql, 0, strcspn( $sql, " \t\r\n" ) );
1054 return !in_array( $verb, array( 'BEGIN', 'COMMIT', 'ROLLBACK', 'SHOW', 'SET' ) );
1055 }
1056
1057 /**
1058 * Run an SQL query and return the result. Normally throws a DBQueryError
1059 * on failure. If errors are ignored, returns false instead.
1060 *
1061 * In new code, the query wrappers select(), insert(), update(), delete(),
1062 * etc. should be used where possible, since they give much better DBMS
1063 * independence and automatically quote or validate user input in a variety
1064 * of contexts. This function is generally only useful for queries which are
1065 * explicitly DBMS-dependent and are unsupported by the query wrappers, such
1066 * as CREATE TABLE.
1067 *
1068 * However, the query wrappers themselves should call this function.
1069 *
1070 * @param string $sql SQL query
1071 * @param string $fname Name of the calling function, for profiling/SHOW PROCESSLIST
1072 * comment (you can use __METHOD__ or add some extra info)
1073 * @param bool $tempIgnore Whether to avoid throwing an exception on errors...
1074 * maybe best to catch the exception instead?
1075 * @throws MWException
1076 * @return bool|ResultWrapper True for a successful write query, ResultWrapper object
1077 * for a successful read query, or false on failure if $tempIgnore set
1078 */
1079 public function query( $sql, $fname = __METHOD__, $tempIgnore = false ) {
1080 global $wgUser, $wgDebugDBTransactions, $wgDebugDumpSqlLength;
1081
1082 $this->mLastQuery = $sql;
1083
1084 $isWriteQuery = $this->isWriteQuery( $sql );
1085 if ( $isWriteQuery ) {
1086 # Set a flag indicating that writes have been done
1087 wfDebug( __METHOD__ . ': Writes done: ' . DatabaseBase::generalizeSQL( $sql ) . "\n" );
1088 $this->mDoneWrites = microtime( true );
1089 }
1090
1091 # Add a comment for easy SHOW PROCESSLIST interpretation
1092 if ( is_object( $wgUser ) && $wgUser->isItemLoaded( 'name' ) ) {
1093 $userName = $wgUser->getName();
1094 if ( mb_strlen( $userName ) > 15 ) {
1095 $userName = mb_substr( $userName, 0, 15 ) . '...';
1096 }
1097 $userName = str_replace( '/', '', $userName );
1098 } else {
1099 $userName = '';
1100 }
1101
1102 // Add trace comment to the begin of the sql string, right after the operator.
1103 // Or, for one-word queries (like "BEGIN" or COMMIT") add it to the end (bug 42598)
1104 $commentedSql = preg_replace( '/\s|$/', " /* $fname $userName */ ", $sql, 1 );
1105
1106 if ( !$this->mTrxLevel && $this->getFlag( DBO_TRX ) && $this->isTransactableQuery( $sql ) ) {
1107 if ( $wgDebugDBTransactions ) {
1108 wfDebug( "Implicit transaction start.\n" );
1109 }
1110 $this->begin( __METHOD__ . " ($fname)" );
1111 $this->mTrxAutomatic = true;
1112 }
1113
1114 # Keep track of whether the transaction has write queries pending
1115 if ( $this->mTrxLevel && !$this->mTrxDoneWrites && $isWriteQuery ) {
1116 $this->mTrxDoneWrites = true;
1117 Profiler::instance()->getTransactionProfiler()->transactionWritingIn(
1118 $this->mServer, $this->mDBname, $this->mTrxShortId );
1119 }
1120
1121 $queryProf = '';
1122 $totalProf = '';
1123 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
1124
1125 $profiler = Profiler::instance();
1126 if ( !$profiler instanceof ProfilerStub ) {
1127 # generalizeSQL will probably cut down the query to reasonable
1128 # logging size most of the time. The substr is really just a sanity check.
1129 if ( $isMaster ) {
1130 $queryProf = 'query-m: ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
1131 $totalProf = 'DatabaseBase::query-master';
1132 } else {
1133 $queryProf = 'query: ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
1134 $totalProf = 'DatabaseBase::query';
1135 }
1136 # Include query transaction state
1137 $queryProf .= $this->mTrxShortId ? " [TRX#{$this->mTrxShortId}]" : "";
1138
1139 $totalProfSection = $profiler->scopedProfileIn( $totalProf );
1140 $queryProfSection = $profiler->scopedProfileIn( $queryProf );
1141 }
1142
1143 if ( $this->debug() ) {
1144 static $cnt = 0;
1145
1146 $cnt++;
1147 $sqlx = $wgDebugDumpSqlLength ? substr( $commentedSql, 0, $wgDebugDumpSqlLength )
1148 : $commentedSql;
1149 $sqlx = strtr( $sqlx, "\t\n", ' ' );
1150
1151 $master = $isMaster ? 'master' : 'slave';
1152 wfDebug( "Query {$this->mDBname} ($cnt) ($master): $sqlx\n" );
1153 }
1154
1155 $queryId = MWDebug::query( $sql, $fname, $isMaster );
1156
1157 # Avoid fatals if close() was called
1158 if ( !$this->isOpen() ) {
1159 throw new DBUnexpectedError( $this, "DB connection was already closed." );
1160 }
1161
1162 # Log the query time and feed it into the DB trx profiler
1163 if ( $queryProf != '' ) {
1164 $that = $this;
1165 $queryStartTime = microtime( true );
1166 $queryProfile = new ScopedCallback(
1167 function () use ( $that, $queryStartTime, $queryProf, $isMaster ) {
1168 $n = $that->affectedRows();
1169 $trxProf = Profiler::instance()->getTransactionProfiler();
1170 $trxProf->recordQueryCompletion( $queryProf, $queryStartTime, $isMaster, $n );
1171 }
1172 );
1173 }
1174
1175 # Do the query and handle errors
1176 $ret = $this->doQuery( $commentedSql );
1177
1178 MWDebug::queryTime( $queryId );
1179
1180 # Try reconnecting if the connection was lost
1181 if ( false === $ret && $this->wasErrorReissuable() ) {
1182 # Transaction is gone, like it or not
1183 $hadTrx = $this->mTrxLevel; // possible lost transaction
1184 $this->mTrxLevel = 0;
1185 $this->mTrxIdleCallbacks = array(); // bug 65263
1186 $this->mTrxPreCommitCallbacks = array(); // bug 65263
1187 wfDebug( "Connection lost, reconnecting...\n" );
1188 # Stash the last error values since ping() might clear them
1189 $lastError = $this->lastError();
1190 $lastErrno = $this->lastErrno();
1191 if ( $this->ping() ) {
1192 wfDebug( "Reconnected\n" );
1193 $server = $this->getServer();
1194 $msg = __METHOD__ . ": lost connection to $server; reconnected";
1195 wfDebugLog( 'DBPerformance', "$msg:\n" . wfBacktrace( true ) );
1196
1197 if ( $hadTrx ) {
1198 # Leave $ret as false and let an error be reported.
1199 # Callers may catch the exception and continue to use the DB.
1200 $this->reportQueryError( $lastError, $lastErrno, $sql, $fname, $tempIgnore );
1201 } else {
1202 # Should be safe to silently retry (no trx and thus no callbacks)
1203 $ret = $this->doQuery( $commentedSql );
1204 }
1205 } else {
1206 wfDebug( "Failed\n" );
1207 }
1208 }
1209
1210 if ( false === $ret ) {
1211 $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
1212 }
1213
1214 $res = $this->resultObject( $ret );
1215
1216 // Destroy profile sections in the opposite order to their creation
1217 $queryProfSection = false;
1218 $totalProfSection = false;
1219
1220 return $res;
1221 }
1222
1223 /**
1224 * Report a query error. Log the error, and if neither the object ignore
1225 * flag nor the $tempIgnore flag is set, throw a DBQueryError.
1226 *
1227 * @param string $error
1228 * @param int $errno
1229 * @param string $sql
1230 * @param string $fname
1231 * @param bool $tempIgnore
1232 * @throws DBQueryError
1233 */
1234 public function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
1235 # Ignore errors during error handling to avoid infinite recursion
1236 $ignore = $this->ignoreErrors( true );
1237 ++$this->mErrorCount;
1238
1239 if ( $ignore || $tempIgnore ) {
1240 wfDebug( "SQL ERROR (ignored): $error\n" );
1241 $this->ignoreErrors( $ignore );
1242 } else {
1243 $sql1line = mb_substr( str_replace( "\n", "\\n", $sql ), 0, 5 * 1024 );
1244 wfLogDBError(
1245 "{fname}\t{db_server}\t{errno}\t{error}\t{sql1line}",
1246 $this->getLogContext( array(
1247 'method' => __METHOD__,
1248 'errno' => $errno,
1249 'error' => $error,
1250 'sql1line' => $sql1line,
1251 'fname' => $fname,
1252 ) )
1253 );
1254 wfDebug( "SQL ERROR: " . $error . "\n" );
1255 throw new DBQueryError( $this, $error, $errno, $sql, $fname );
1256 }
1257 }
1258
1259 /**
1260 * Intended to be compatible with the PEAR::DB wrapper functions.
1261 * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1262 *
1263 * ? = scalar value, quoted as necessary
1264 * ! = raw SQL bit (a function for instance)
1265 * & = filename; reads the file and inserts as a blob
1266 * (we don't use this though...)
1267 *
1268 * @param string $sql
1269 * @param string $func
1270 *
1271 * @return array
1272 */
1273 protected function prepare( $sql, $func = 'DatabaseBase::prepare' ) {
1274 /* MySQL doesn't support prepared statements (yet), so just
1275 * pack up the query for reference. We'll manually replace
1276 * the bits later.
1277 */
1278 return array( 'query' => $sql, 'func' => $func );
1279 }
1280
1281 /**
1282 * Free a prepared query, generated by prepare().
1283 * @param string $prepared
1284 */
1285 protected function freePrepared( $prepared ) {
1286 /* No-op by default */
1287 }
1288
1289 /**
1290 * Execute a prepared query with the various arguments
1291 * @param string $prepared The prepared sql
1292 * @param mixed $args Either an array here, or put scalars as varargs
1293 *
1294 * @return ResultWrapper
1295 */
1296 public function execute( $prepared, $args = null ) {
1297 if ( !is_array( $args ) ) {
1298 # Pull the var args
1299 $args = func_get_args();
1300 array_shift( $args );
1301 }
1302
1303 $sql = $this->fillPrepared( $prepared['query'], $args );
1304
1305 return $this->query( $sql, $prepared['func'] );
1306 }
1307
1308 /**
1309 * For faking prepared SQL statements on DBs that don't support it directly.
1310 *
1311 * @param string $preparedQuery A 'preparable' SQL statement
1312 * @param array $args Array of Arguments to fill it with
1313 * @return string Executable SQL
1314 */
1315 public function fillPrepared( $preparedQuery, $args ) {
1316 reset( $args );
1317 $this->preparedArgs =& $args;
1318
1319 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
1320 array( &$this, 'fillPreparedArg' ), $preparedQuery );
1321 }
1322
1323 /**
1324 * preg_callback func for fillPrepared()
1325 * The arguments should be in $this->preparedArgs and must not be touched
1326 * while we're doing this.
1327 *
1328 * @param array $matches
1329 * @throws DBUnexpectedError
1330 * @return string
1331 */
1332 protected function fillPreparedArg( $matches ) {
1333 switch ( $matches[1] ) {
1334 case '\\?':
1335 return '?';
1336 case '\\!':
1337 return '!';
1338 case '\\&':
1339 return '&';
1340 }
1341
1342 list( /* $n */, $arg ) = each( $this->preparedArgs );
1343
1344 switch ( $matches[1] ) {
1345 case '?':
1346 return $this->addQuotes( $arg );
1347 case '!':
1348 return $arg;
1349 case '&':
1350 # return $this->addQuotes( file_get_contents( $arg ) );
1351 throw new DBUnexpectedError(
1352 $this,
1353 '& mode is not implemented. If it\'s really needed, uncomment the line above.'
1354 );
1355 default:
1356 throw new DBUnexpectedError(
1357 $this,
1358 'Received invalid match. This should never happen!'
1359 );
1360 }
1361 }
1362
1363 /**
1364 * Free a result object returned by query() or select(). It's usually not
1365 * necessary to call this, just use unset() or let the variable holding
1366 * the result object go out of scope.
1367 *
1368 * @param mixed $res A SQL result
1369 */
1370 public function freeResult( $res ) {
1371 }
1372
1373 /**
1374 * A SELECT wrapper which returns a single field from a single result row.
1375 *
1376 * Usually throws a DBQueryError on failure. If errors are explicitly
1377 * ignored, returns false on failure.
1378 *
1379 * If no result rows are returned from the query, false is returned.
1380 *
1381 * @param string|array $table Table name. See DatabaseBase::select() for details.
1382 * @param string $var The field name to select. This must be a valid SQL
1383 * fragment: do not use unvalidated user input.
1384 * @param string|array $cond The condition array. See DatabaseBase::select() for details.
1385 * @param string $fname The function name of the caller.
1386 * @param string|array $options The query options. See DatabaseBase::select() for details.
1387 *
1388 * @return bool|mixed The value from the field, or false on failure.
1389 */
1390 public function selectField( $table, $var, $cond = '', $fname = __METHOD__,
1391 $options = array()
1392 ) {
1393 if ( !is_array( $options ) ) {
1394 $options = array( $options );
1395 }
1396
1397 $options['LIMIT'] = 1;
1398
1399 $res = $this->select( $table, $var, $cond, $fname, $options );
1400
1401 if ( $res === false || !$this->numRows( $res ) ) {
1402 return false;
1403 }
1404
1405 $row = $this->fetchRow( $res );
1406
1407 if ( $row !== false ) {
1408 return reset( $row );
1409 } else {
1410 return false;
1411 }
1412 }
1413
1414 /**
1415 * Returns an optional USE INDEX clause to go after the table, and a
1416 * string to go at the end of the query.
1417 *
1418 * @param array $options Associative array of options to be turned into
1419 * an SQL query, valid keys are listed in the function.
1420 * @return array
1421 * @see DatabaseBase::select()
1422 */
1423 public function makeSelectOptions( $options ) {
1424 $preLimitTail = $postLimitTail = '';
1425 $startOpts = '';
1426
1427 $noKeyOptions = array();
1428
1429 foreach ( $options as $key => $option ) {
1430 if ( is_numeric( $key ) ) {
1431 $noKeyOptions[$option] = true;
1432 }
1433 }
1434
1435 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1436
1437 $preLimitTail .= $this->makeOrderBy( $options );
1438
1439 // if (isset($options['LIMIT'])) {
1440 // $tailOpts .= $this->limitResult('', $options['LIMIT'],
1441 // isset($options['OFFSET']) ? $options['OFFSET']
1442 // : false);
1443 // }
1444
1445 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1446 $postLimitTail .= ' FOR UPDATE';
1447 }
1448
1449 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) {
1450 $postLimitTail .= ' LOCK IN SHARE MODE';
1451 }
1452
1453 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1454 $startOpts .= 'DISTINCT';
1455 }
1456
1457 # Various MySQL extensions
1458 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) {
1459 $startOpts .= ' /*! STRAIGHT_JOIN */';
1460 }
1461
1462 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) {
1463 $startOpts .= ' HIGH_PRIORITY';
1464 }
1465
1466 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) {
1467 $startOpts .= ' SQL_BIG_RESULT';
1468 }
1469
1470 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) {
1471 $startOpts .= ' SQL_BUFFER_RESULT';
1472 }
1473
1474 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) {
1475 $startOpts .= ' SQL_SMALL_RESULT';
1476 }
1477
1478 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) {
1479 $startOpts .= ' SQL_CALC_FOUND_ROWS';
1480 }
1481
1482 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) {
1483 $startOpts .= ' SQL_CACHE';
1484 }
1485
1486 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) {
1487 $startOpts .= ' SQL_NO_CACHE';
1488 }
1489
1490 if ( isset( $options['USE INDEX'] ) && is_string( $options['USE INDEX'] ) ) {
1491 $useIndex = $this->useIndexClause( $options['USE INDEX'] );
1492 } else {
1493 $useIndex = '';
1494 }
1495
1496 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1497 }
1498
1499 /**
1500 * Returns an optional GROUP BY with an optional HAVING
1501 *
1502 * @param array $options Associative array of options
1503 * @return string
1504 * @see DatabaseBase::select()
1505 * @since 1.21
1506 */
1507 public function makeGroupByWithHaving( $options ) {
1508 $sql = '';
1509 if ( isset( $options['GROUP BY'] ) ) {
1510 $gb = is_array( $options['GROUP BY'] )
1511 ? implode( ',', $options['GROUP BY'] )
1512 : $options['GROUP BY'];
1513 $sql .= ' GROUP BY ' . $gb;
1514 }
1515 if ( isset( $options['HAVING'] ) ) {
1516 $having = is_array( $options['HAVING'] )
1517 ? $this->makeList( $options['HAVING'], LIST_AND )
1518 : $options['HAVING'];
1519 $sql .= ' HAVING ' . $having;
1520 }
1521
1522 return $sql;
1523 }
1524
1525 /**
1526 * Returns an optional ORDER BY
1527 *
1528 * @param array $options Associative array of options
1529 * @return string
1530 * @see DatabaseBase::select()
1531 * @since 1.21
1532 */
1533 public function makeOrderBy( $options ) {
1534 if ( isset( $options['ORDER BY'] ) ) {
1535 $ob = is_array( $options['ORDER BY'] )
1536 ? implode( ',', $options['ORDER BY'] )
1537 : $options['ORDER BY'];
1538
1539 return ' ORDER BY ' . $ob;
1540 }
1541
1542 return '';
1543 }
1544
1545 /**
1546 * Execute a SELECT query constructed using the various parameters provided.
1547 * See below for full details of the parameters.
1548 *
1549 * @param string|array $table Table name
1550 * @param string|array $vars Field names
1551 * @param string|array $conds Conditions
1552 * @param string $fname Caller function name
1553 * @param array $options Query options
1554 * @param array $join_conds Join conditions
1555 *
1556 *
1557 * @param string|array $table
1558 *
1559 * May be either an array of table names, or a single string holding a table
1560 * name. If an array is given, table aliases can be specified, for example:
1561 *
1562 * array( 'a' => 'user' )
1563 *
1564 * This includes the user table in the query, with the alias "a" available
1565 * for use in field names (e.g. a.user_name).
1566 *
1567 * All of the table names given here are automatically run through
1568 * DatabaseBase::tableName(), which causes the table prefix (if any) to be
1569 * added, and various other table name mappings to be performed.
1570 *
1571 *
1572 * @param string|array $vars
1573 *
1574 * May be either a field name or an array of field names. The field names
1575 * can be complete fragments of SQL, for direct inclusion into the SELECT
1576 * query. If an array is given, field aliases can be specified, for example:
1577 *
1578 * array( 'maxrev' => 'MAX(rev_id)' )
1579 *
1580 * This includes an expression with the alias "maxrev" in the query.
1581 *
1582 * If an expression is given, care must be taken to ensure that it is
1583 * DBMS-independent.
1584 *
1585 *
1586 * @param string|array $conds
1587 *
1588 * May be either a string containing a single condition, or an array of
1589 * conditions. If an array is given, the conditions constructed from each
1590 * element are combined with AND.
1591 *
1592 * Array elements may take one of two forms:
1593 *
1594 * - Elements with a numeric key are interpreted as raw SQL fragments.
1595 * - Elements with a string key are interpreted as equality conditions,
1596 * where the key is the field name.
1597 * - If the value of such an array element is a scalar (such as a
1598 * string), it will be treated as data and thus quoted appropriately.
1599 * If it is null, an IS NULL clause will be added.
1600 * - If the value is an array, an IN(...) clause will be constructed,
1601 * such that the field name may match any of the elements in the
1602 * array. The elements of the array will be quoted.
1603 *
1604 * Note that expressions are often DBMS-dependent in their syntax.
1605 * DBMS-independent wrappers are provided for constructing several types of
1606 * expression commonly used in condition queries. See:
1607 * - DatabaseBase::buildLike()
1608 * - DatabaseBase::conditional()
1609 *
1610 *
1611 * @param string|array $options
1612 *
1613 * Optional: Array of query options. Boolean options are specified by
1614 * including them in the array as a string value with a numeric key, for
1615 * example:
1616 *
1617 * array( 'FOR UPDATE' )
1618 *
1619 * The supported options are:
1620 *
1621 * - OFFSET: Skip this many rows at the start of the result set. OFFSET
1622 * with LIMIT can theoretically be used for paging through a result set,
1623 * but this is discouraged in MediaWiki for performance reasons.
1624 *
1625 * - LIMIT: Integer: return at most this many rows. The rows are sorted
1626 * and then the first rows are taken until the limit is reached. LIMIT
1627 * is applied to a result set after OFFSET.
1628 *
1629 * - FOR UPDATE: Boolean: lock the returned rows so that they can't be
1630 * changed until the next COMMIT.
1631 *
1632 * - DISTINCT: Boolean: return only unique result rows.
1633 *
1634 * - GROUP BY: May be either an SQL fragment string naming a field or
1635 * expression to group by, or an array of such SQL fragments.
1636 *
1637 * - HAVING: May be either an string containing a HAVING clause or an array of
1638 * conditions building the HAVING clause. If an array is given, the conditions
1639 * constructed from each element are combined with AND.
1640 *
1641 * - ORDER BY: May be either an SQL fragment giving a field name or
1642 * expression to order by, or an array of such SQL fragments.
1643 *
1644 * - USE INDEX: This may be either a string giving the index name to use
1645 * for the query, or an array. If it is an associative array, each key
1646 * gives the table name (or alias), each value gives the index name to
1647 * use for that table. All strings are SQL fragments and so should be
1648 * validated by the caller.
1649 *
1650 * - EXPLAIN: In MySQL, this causes an EXPLAIN SELECT query to be run,
1651 * instead of SELECT.
1652 *
1653 * And also the following boolean MySQL extensions, see the MySQL manual
1654 * for documentation:
1655 *
1656 * - LOCK IN SHARE MODE
1657 * - STRAIGHT_JOIN
1658 * - HIGH_PRIORITY
1659 * - SQL_BIG_RESULT
1660 * - SQL_BUFFER_RESULT
1661 * - SQL_SMALL_RESULT
1662 * - SQL_CALC_FOUND_ROWS
1663 * - SQL_CACHE
1664 * - SQL_NO_CACHE
1665 *
1666 *
1667 * @param string|array $join_conds
1668 *
1669 * Optional associative array of table-specific join conditions. In the
1670 * most common case, this is unnecessary, since the join condition can be
1671 * in $conds. However, it is useful for doing a LEFT JOIN.
1672 *
1673 * The key of the array contains the table name or alias. The value is an
1674 * array with two elements, numbered 0 and 1. The first gives the type of
1675 * join, the second is an SQL fragment giving the join condition for that
1676 * table. For example:
1677 *
1678 * array( 'page' => array( 'LEFT JOIN', 'page_latest=rev_id' ) )
1679 *
1680 * @return ResultWrapper|bool If the query returned no rows, a ResultWrapper
1681 * with no rows in it will be returned. If there was a query error, a
1682 * DBQueryError exception will be thrown, except if the "ignore errors"
1683 * option was set, in which case false will be returned.
1684 */
1685 public function select( $table, $vars, $conds = '', $fname = __METHOD__,
1686 $options = array(), $join_conds = array() ) {
1687 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
1688
1689 return $this->query( $sql, $fname );
1690 }
1691
1692 /**
1693 * The equivalent of DatabaseBase::select() except that the constructed SQL
1694 * is returned, instead of being immediately executed. This can be useful for
1695 * doing UNION queries, where the SQL text of each query is needed. In general,
1696 * however, callers outside of Database classes should just use select().
1697 *
1698 * @param string|array $table Table name
1699 * @param string|array $vars Field names
1700 * @param string|array $conds Conditions
1701 * @param string $fname Caller function name
1702 * @param string|array $options Query options
1703 * @param string|array $join_conds Join conditions
1704 *
1705 * @return string SQL query string.
1706 * @see DatabaseBase::select()
1707 */
1708 public function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
1709 $options = array(), $join_conds = array()
1710 ) {
1711 if ( is_array( $vars ) ) {
1712 $vars = implode( ',', $this->fieldNamesWithAlias( $vars ) );
1713 }
1714
1715 $options = (array)$options;
1716 $useIndexes = ( isset( $options['USE INDEX'] ) && is_array( $options['USE INDEX'] ) )
1717 ? $options['USE INDEX']
1718 : array();
1719
1720 if ( is_array( $table ) ) {
1721 $from = ' FROM ' .
1722 $this->tableNamesWithUseIndexOrJOIN( $table, $useIndexes, $join_conds );
1723 } elseif ( $table != '' ) {
1724 if ( $table[0] == ' ' ) {
1725 $from = ' FROM ' . $table;
1726 } else {
1727 $from = ' FROM ' .
1728 $this->tableNamesWithUseIndexOrJOIN( array( $table ), $useIndexes, array() );
1729 }
1730 } else {
1731 $from = '';
1732 }
1733
1734 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) =
1735 $this->makeSelectOptions( $options );
1736
1737 if ( !empty( $conds ) ) {
1738 if ( is_array( $conds ) ) {
1739 $conds = $this->makeList( $conds, LIST_AND );
1740 }
1741 $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
1742 } else {
1743 $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
1744 }
1745
1746 if ( isset( $options['LIMIT'] ) ) {
1747 $sql = $this->limitResult( $sql, $options['LIMIT'],
1748 isset( $options['OFFSET'] ) ? $options['OFFSET'] : false );
1749 }
1750 $sql = "$sql $postLimitTail";
1751
1752 if ( isset( $options['EXPLAIN'] ) ) {
1753 $sql = 'EXPLAIN ' . $sql;
1754 }
1755
1756 return $sql;
1757 }
1758
1759 /**
1760 * Single row SELECT wrapper. Equivalent to DatabaseBase::select(), except
1761 * that a single row object is returned. If the query returns no rows,
1762 * false is returned.
1763 *
1764 * @param string|array $table Table name
1765 * @param string|array $vars Field names
1766 * @param array $conds Conditions
1767 * @param string $fname Caller function name
1768 * @param string|array $options Query options
1769 * @param array|string $join_conds Join conditions
1770 *
1771 * @return stdClass|bool
1772 */
1773 public function selectRow( $table, $vars, $conds, $fname = __METHOD__,
1774 $options = array(), $join_conds = array()
1775 ) {
1776 $options = (array)$options;
1777 $options['LIMIT'] = 1;
1778 $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
1779
1780 if ( $res === false ) {
1781 return false;
1782 }
1783
1784 if ( !$this->numRows( $res ) ) {
1785 return false;
1786 }
1787
1788 $obj = $this->fetchObject( $res );
1789
1790 return $obj;
1791 }
1792
1793 /**
1794 * Estimate the number of rows in dataset
1795 *
1796 * MySQL allows you to estimate the number of rows that would be returned
1797 * by a SELECT query, using EXPLAIN SELECT. The estimate is provided using
1798 * index cardinality statistics, and is notoriously inaccurate, especially
1799 * when large numbers of rows have recently been added or deleted.
1800 *
1801 * For DBMSs that don't support fast result size estimation, this function
1802 * will actually perform the SELECT COUNT(*).
1803 *
1804 * Takes the same arguments as DatabaseBase::select().
1805 *
1806 * @param string $table Table name
1807 * @param string $vars Unused
1808 * @param array|string $conds Filters on the table
1809 * @param string $fname Function name for profiling
1810 * @param array $options Options for select
1811 * @return int Row count
1812 */
1813 public function estimateRowCount(
1814 $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = array()
1815 ) {
1816 $rows = 0;
1817 $res = $this->select( $table, array( 'rowcount' => 'COUNT(*)' ), $conds, $fname, $options );
1818
1819 if ( $res ) {
1820 $row = $this->fetchRow( $res );
1821 $rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
1822 }
1823
1824 return $rows;
1825 }
1826
1827 /**
1828 * Get the number of rows in dataset
1829 *
1830 * This is useful when trying to do COUNT(*) but with a LIMIT for performance.
1831 *
1832 * Takes the same arguments as DatabaseBase::select().
1833 *
1834 * @param string $table Table name
1835 * @param string $vars Unused
1836 * @param array|string $conds Filters on the table
1837 * @param string $fname Function name for profiling
1838 * @param array $options Options for select
1839 * @return int Row count
1840 * @since 1.24
1841 */
1842 public function selectRowCount(
1843 $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = array()
1844 ) {
1845 $rows = 0;
1846 $sql = $this->selectSQLText( $table, '1', $conds, $fname, $options );
1847 $res = $this->query( "SELECT COUNT(*) AS rowcount FROM ($sql) tmp_count" );
1848
1849 if ( $res ) {
1850 $row = $this->fetchRow( $res );
1851 $rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
1852 }
1853
1854 return $rows;
1855 }
1856
1857 /**
1858 * Removes most variables from an SQL query and replaces them with X or N for numbers.
1859 * It's only slightly flawed. Don't use for anything important.
1860 *
1861 * @param string $sql A SQL Query
1862 *
1863 * @return string
1864 */
1865 static function generalizeSQL( $sql ) {
1866 # This does the same as the regexp below would do, but in such a way
1867 # as to avoid crashing php on some large strings.
1868 # $sql = preg_replace( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql );
1869
1870 $sql = str_replace( "\\\\", '', $sql );
1871 $sql = str_replace( "\\'", '', $sql );
1872 $sql = str_replace( "\\\"", '', $sql );
1873 $sql = preg_replace( "/'.*'/s", "'X'", $sql );
1874 $sql = preg_replace( '/".*"/s', "'X'", $sql );
1875
1876 # All newlines, tabs, etc replaced by single space
1877 $sql = preg_replace( '/\s+/', ' ', $sql );
1878
1879 # All numbers => N,
1880 # except the ones surrounded by characters, e.g. l10n
1881 $sql = preg_replace( '/-?\d+(,-?\d+)+/s', 'N,...,N', $sql );
1882 $sql = preg_replace( '/(?<![a-zA-Z])-?\d+(?![a-zA-Z])/s', 'N', $sql );
1883
1884 return $sql;
1885 }
1886
1887 /**
1888 * Determines whether a field exists in a table
1889 *
1890 * @param string $table Table name
1891 * @param string $field Filed to check on that table
1892 * @param string $fname Calling function name (optional)
1893 * @return bool Whether $table has filed $field
1894 */
1895 public function fieldExists( $table, $field, $fname = __METHOD__ ) {
1896 $info = $this->fieldInfo( $table, $field );
1897
1898 return (bool)$info;
1899 }
1900
1901 /**
1902 * Determines whether an index exists
1903 * Usually throws a DBQueryError on failure
1904 * If errors are explicitly ignored, returns NULL on failure
1905 *
1906 * @param string $table
1907 * @param string $index
1908 * @param string $fname
1909 * @return bool|null
1910 */
1911 public function indexExists( $table, $index, $fname = __METHOD__ ) {
1912 if ( !$this->tableExists( $table ) ) {
1913 return null;
1914 }
1915
1916 $info = $this->indexInfo( $table, $index, $fname );
1917 if ( is_null( $info ) ) {
1918 return null;
1919 } else {
1920 return $info !== false;
1921 }
1922 }
1923
1924 /**
1925 * Query whether a given table exists
1926 *
1927 * @param string $table
1928 * @param string $fname
1929 * @return bool
1930 */
1931 public function tableExists( $table, $fname = __METHOD__ ) {
1932 $table = $this->tableName( $table );
1933 $old = $this->ignoreErrors( true );
1934 $res = $this->query( "SELECT 1 FROM $table LIMIT 1", $fname );
1935 $this->ignoreErrors( $old );
1936
1937 return (bool)$res;
1938 }
1939
1940 /**
1941 * Determines if a given index is unique
1942 *
1943 * @param string $table
1944 * @param string $index
1945 *
1946 * @return bool
1947 */
1948 public function indexUnique( $table, $index ) {
1949 $indexInfo = $this->indexInfo( $table, $index );
1950
1951 if ( !$indexInfo ) {
1952 return null;
1953 }
1954
1955 return !$indexInfo[0]->Non_unique;
1956 }
1957
1958 /**
1959 * Helper for DatabaseBase::insert().
1960 *
1961 * @param array $options
1962 * @return string
1963 */
1964 protected function makeInsertOptions( $options ) {
1965 return implode( ' ', $options );
1966 }
1967
1968 /**
1969 * INSERT wrapper, inserts an array into a table.
1970 *
1971 * $a may be either:
1972 *
1973 * - A single associative array. The array keys are the field names, and
1974 * the values are the values to insert. The values are treated as data
1975 * and will be quoted appropriately. If NULL is inserted, this will be
1976 * converted to a database NULL.
1977 * - An array with numeric keys, holding a list of associative arrays.
1978 * This causes a multi-row INSERT on DBMSs that support it. The keys in
1979 * each subarray must be identical to each other, and in the same order.
1980 *
1981 * Usually throws a DBQueryError on failure. If errors are explicitly ignored,
1982 * returns success.
1983 *
1984 * $options is an array of options, with boolean options encoded as values
1985 * with numeric keys, in the same style as $options in
1986 * DatabaseBase::select(). Supported options are:
1987 *
1988 * - IGNORE: Boolean: if present, duplicate key errors are ignored, and
1989 * any rows which cause duplicate key errors are not inserted. It's
1990 * possible to determine how many rows were successfully inserted using
1991 * DatabaseBase::affectedRows().
1992 *
1993 * @param string $table Table name. This will be passed through
1994 * DatabaseBase::tableName().
1995 * @param array $a Array of rows to insert
1996 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
1997 * @param array $options Array of options
1998 *
1999 * @return bool
2000 */
2001 public function insert( $table, $a, $fname = __METHOD__, $options = array() ) {
2002 # No rows to insert, easy just return now
2003 if ( !count( $a ) ) {
2004 return true;
2005 }
2006
2007 $table = $this->tableName( $table );
2008
2009 if ( !is_array( $options ) ) {
2010 $options = array( $options );
2011 }
2012
2013 $fh = null;
2014 if ( isset( $options['fileHandle'] ) ) {
2015 $fh = $options['fileHandle'];
2016 }
2017 $options = $this->makeInsertOptions( $options );
2018
2019 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
2020 $multi = true;
2021 $keys = array_keys( $a[0] );
2022 } else {
2023 $multi = false;
2024 $keys = array_keys( $a );
2025 }
2026
2027 $sql = 'INSERT ' . $options .
2028 " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
2029
2030 if ( $multi ) {
2031 $first = true;
2032 foreach ( $a as $row ) {
2033 if ( $first ) {
2034 $first = false;
2035 } else {
2036 $sql .= ',';
2037 }
2038 $sql .= '(' . $this->makeList( $row ) . ')';
2039 }
2040 } else {
2041 $sql .= '(' . $this->makeList( $a ) . ')';
2042 }
2043
2044 if ( $fh !== null && false === fwrite( $fh, $sql ) ) {
2045 return false;
2046 } elseif ( $fh !== null ) {
2047 return true;
2048 }
2049
2050 return (bool)$this->query( $sql, $fname );
2051 }
2052
2053 /**
2054 * Make UPDATE options array for DatabaseBase::makeUpdateOptions
2055 *
2056 * @param array $options
2057 * @return array
2058 */
2059 protected function makeUpdateOptionsArray( $options ) {
2060 if ( !is_array( $options ) ) {
2061 $options = array( $options );
2062 }
2063
2064 $opts = array();
2065
2066 if ( in_array( 'LOW_PRIORITY', $options ) ) {
2067 $opts[] = $this->lowPriorityOption();
2068 }
2069
2070 if ( in_array( 'IGNORE', $options ) ) {
2071 $opts[] = 'IGNORE';
2072 }
2073
2074 return $opts;
2075 }
2076
2077 /**
2078 * Make UPDATE options for the DatabaseBase::update function
2079 *
2080 * @param array $options The options passed to DatabaseBase::update
2081 * @return string
2082 */
2083 protected function makeUpdateOptions( $options ) {
2084 $opts = $this->makeUpdateOptionsArray( $options );
2085
2086 return implode( ' ', $opts );
2087 }
2088
2089 /**
2090 * UPDATE wrapper. Takes a condition array and a SET array.
2091 *
2092 * @param string $table Name of the table to UPDATE. This will be passed through
2093 * DatabaseBase::tableName().
2094 * @param array $values An array of values to SET. For each array element,
2095 * the key gives the field name, and the value gives the data to set
2096 * that field to. The data will be quoted by DatabaseBase::addQuotes().
2097 * @param array $conds An array of conditions (WHERE). See
2098 * DatabaseBase::select() for the details of the format of condition
2099 * arrays. Use '*' to update all rows.
2100 * @param string $fname The function name of the caller (from __METHOD__),
2101 * for logging and profiling.
2102 * @param array $options An array of UPDATE options, can be:
2103 * - IGNORE: Ignore unique key conflicts
2104 * - LOW_PRIORITY: MySQL-specific, see MySQL manual.
2105 * @return bool
2106 */
2107 function update( $table, $values, $conds, $fname = __METHOD__, $options = array() ) {
2108 $table = $this->tableName( $table );
2109 $opts = $this->makeUpdateOptions( $options );
2110 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
2111
2112 if ( $conds !== array() && $conds !== '*' ) {
2113 $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
2114 }
2115
2116 return $this->query( $sql, $fname );
2117 }
2118
2119 /**
2120 * Makes an encoded list of strings from an array
2121 *
2122 * @param array $a Containing the data
2123 * @param int $mode Constant
2124 * - LIST_COMMA: Comma separated, no field names
2125 * - LIST_AND: ANDed WHERE clause (without the WHERE). See the
2126 * documentation for $conds in DatabaseBase::select().
2127 * - LIST_OR: ORed WHERE clause (without the WHERE)
2128 * - LIST_SET: Comma separated with field names, like a SET clause
2129 * - LIST_NAMES: Comma separated field names
2130 * @throws MWException|DBUnexpectedError
2131 * @return string
2132 */
2133 public function makeList( $a, $mode = LIST_COMMA ) {
2134 if ( !is_array( $a ) ) {
2135 throw new DBUnexpectedError( $this, 'DatabaseBase::makeList called with incorrect parameters' );
2136 }
2137
2138 $first = true;
2139 $list = '';
2140
2141 foreach ( $a as $field => $value ) {
2142 if ( !$first ) {
2143 if ( $mode == LIST_AND ) {
2144 $list .= ' AND ';
2145 } elseif ( $mode == LIST_OR ) {
2146 $list .= ' OR ';
2147 } else {
2148 $list .= ',';
2149 }
2150 } else {
2151 $first = false;
2152 }
2153
2154 if ( ( $mode == LIST_AND || $mode == LIST_OR ) && is_numeric( $field ) ) {
2155 $list .= "($value)";
2156 } elseif ( ( $mode == LIST_SET ) && is_numeric( $field ) ) {
2157 $list .= "$value";
2158 } elseif ( ( $mode == LIST_AND || $mode == LIST_OR ) && is_array( $value ) ) {
2159 // Remove null from array to be handled separately if found
2160 $includeNull = false;
2161 foreach ( array_keys( $value, null, true ) as $nullKey ) {
2162 $includeNull = true;
2163 unset( $value[$nullKey] );
2164 }
2165 if ( count( $value ) == 0 && !$includeNull ) {
2166 throw new MWException( __METHOD__ . ": empty input for field $field" );
2167 } elseif ( count( $value ) == 0 ) {
2168 // only check if $field is null
2169 $list .= "$field IS NULL";
2170 } else {
2171 // IN clause contains at least one valid element
2172 if ( $includeNull ) {
2173 // Group subconditions to ensure correct precedence
2174 $list .= '(';
2175 }
2176 if ( count( $value ) == 1 ) {
2177 // Special-case single values, as IN isn't terribly efficient
2178 // Don't necessarily assume the single key is 0; we don't
2179 // enforce linear numeric ordering on other arrays here.
2180 $value = array_values( $value );
2181 $list .= $field . " = " . $this->addQuotes( $value[0] );
2182 } else {
2183 $list .= $field . " IN (" . $this->makeList( $value ) . ") ";
2184 }
2185 // if null present in array, append IS NULL
2186 if ( $includeNull ) {
2187 $list .= " OR $field IS NULL)";
2188 }
2189 }
2190 } elseif ( $value === null ) {
2191 if ( $mode == LIST_AND || $mode == LIST_OR ) {
2192 $list .= "$field IS ";
2193 } elseif ( $mode == LIST_SET ) {
2194 $list .= "$field = ";
2195 }
2196 $list .= 'NULL';
2197 } else {
2198 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
2199 $list .= "$field = ";
2200 }
2201 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
2202 }
2203 }
2204
2205 return $list;
2206 }
2207
2208 /**
2209 * Build a partial where clause from a 2-d array such as used for LinkBatch.
2210 * The keys on each level may be either integers or strings.
2211 *
2212 * @param array $data Organized as 2-d
2213 * array(baseKeyVal => array(subKeyVal => [ignored], ...), ...)
2214 * @param string $baseKey Field name to match the base-level keys to (eg 'pl_namespace')
2215 * @param string $subKey Field name to match the sub-level keys to (eg 'pl_title')
2216 * @return string|bool SQL fragment, or false if no items in array
2217 */
2218 public function makeWhereFrom2d( $data, $baseKey, $subKey ) {
2219 $conds = array();
2220
2221 foreach ( $data as $base => $sub ) {
2222 if ( count( $sub ) ) {
2223 $conds[] = $this->makeList(
2224 array( $baseKey => $base, $subKey => array_keys( $sub ) ),
2225 LIST_AND );
2226 }
2227 }
2228
2229 if ( $conds ) {
2230 return $this->makeList( $conds, LIST_OR );
2231 } else {
2232 // Nothing to search for...
2233 return false;
2234 }
2235 }
2236
2237 /**
2238 * Return aggregated value alias
2239 *
2240 * @param array $valuedata
2241 * @param string $valuename
2242 *
2243 * @return string
2244 */
2245 public function aggregateValue( $valuedata, $valuename = 'value' ) {
2246 return $valuename;
2247 }
2248
2249 /**
2250 * @param string $field
2251 * @return string
2252 */
2253 public function bitNot( $field ) {
2254 return "(~$field)";
2255 }
2256
2257 /**
2258 * @param string $fieldLeft
2259 * @param string $fieldRight
2260 * @return string
2261 */
2262 public function bitAnd( $fieldLeft, $fieldRight ) {
2263 return "($fieldLeft & $fieldRight)";
2264 }
2265
2266 /**
2267 * @param string $fieldLeft
2268 * @param string $fieldRight
2269 * @return string
2270 */
2271 public function bitOr( $fieldLeft, $fieldRight ) {
2272 return "($fieldLeft | $fieldRight)";
2273 }
2274
2275 /**
2276 * Build a concatenation list to feed into a SQL query
2277 * @param array $stringList List of raw SQL expressions; caller is
2278 * responsible for any quoting
2279 * @return string
2280 */
2281 public function buildConcat( $stringList ) {
2282 return 'CONCAT(' . implode( ',', $stringList ) . ')';
2283 }
2284
2285 /**
2286 * Build a GROUP_CONCAT or equivalent statement for a query.
2287 *
2288 * This is useful for combining a field for several rows into a single string.
2289 * NULL values will not appear in the output, duplicated values will appear,
2290 * and the resulting delimiter-separated values have no defined sort order.
2291 * Code using the results may need to use the PHP unique() or sort() methods.
2292 *
2293 * @param string $delim Glue to bind the results together
2294 * @param string|array $table Table name
2295 * @param string $field Field name
2296 * @param string|array $conds Conditions
2297 * @param string|array $join_conds Join conditions
2298 * @return string SQL text
2299 * @since 1.23
2300 */
2301 public function buildGroupConcatField(
2302 $delim, $table, $field, $conds = '', $join_conds = array()
2303 ) {
2304 $fld = "GROUP_CONCAT($field SEPARATOR " . $this->addQuotes( $delim ) . ')';
2305
2306 return '(' . $this->selectSQLText( $table, $fld, $conds, null, array(), $join_conds ) . ')';
2307 }
2308
2309 /**
2310 * Change the current database
2311 *
2312 * @todo Explain what exactly will fail if this is not overridden.
2313 *
2314 * @param string $db
2315 *
2316 * @return bool Success or failure
2317 */
2318 public function selectDB( $db ) {
2319 # Stub. Shouldn't cause serious problems if it's not overridden, but
2320 # if your database engine supports a concept similar to MySQL's
2321 # databases you may as well.
2322 $this->mDBname = $db;
2323
2324 return true;
2325 }
2326
2327 /**
2328 * Get the current DB name
2329 * @return string
2330 */
2331 public function getDBname() {
2332 return $this->mDBname;
2333 }
2334
2335 /**
2336 * Get the server hostname or IP address
2337 * @return string
2338 */
2339 public function getServer() {
2340 return $this->mServer;
2341 }
2342
2343 /**
2344 * Format a table name ready for use in constructing an SQL query
2345 *
2346 * This does two important things: it quotes the table names to clean them up,
2347 * and it adds a table prefix if only given a table name with no quotes.
2348 *
2349 * All functions of this object which require a table name call this function
2350 * themselves. Pass the canonical name to such functions. This is only needed
2351 * when calling query() directly.
2352 *
2353 * @param string $name Database table name
2354 * @param string $format One of:
2355 * quoted - Automatically pass the table name through addIdentifierQuotes()
2356 * so that it can be used in a query.
2357 * raw - Do not add identifier quotes to the table name
2358 * @return string Full database name
2359 */
2360 public function tableName( $name, $format = 'quoted' ) {
2361 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables, $wgSharedSchema;
2362 # Skip the entire process when we have a string quoted on both ends.
2363 # Note that we check the end so that we will still quote any use of
2364 # use of `database`.table. But won't break things if someone wants
2365 # to query a database table with a dot in the name.
2366 if ( $this->isQuotedIdentifier( $name ) ) {
2367 return $name;
2368 }
2369
2370 # Lets test for any bits of text that should never show up in a table
2371 # name. Basically anything like JOIN or ON which are actually part of
2372 # SQL queries, but may end up inside of the table value to combine
2373 # sql. Such as how the API is doing.
2374 # Note that we use a whitespace test rather than a \b test to avoid
2375 # any remote case where a word like on may be inside of a table name
2376 # surrounded by symbols which may be considered word breaks.
2377 if ( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) {
2378 return $name;
2379 }
2380
2381 # Split database and table into proper variables.
2382 # We reverse the explode so that database.table and table both output
2383 # the correct table.
2384 $dbDetails = explode( '.', $name, 3 );
2385 if ( count( $dbDetails ) == 3 ) {
2386 list( $database, $schema, $table ) = $dbDetails;
2387 # We don't want any prefix added in this case
2388 $prefix = '';
2389 } elseif ( count( $dbDetails ) == 2 ) {
2390 list( $database, $table ) = $dbDetails;
2391 # We don't want any prefix added in this case
2392 # In dbs that support it, $database may actually be the schema
2393 # but that doesn't affect any of the functionality here
2394 $prefix = '';
2395 $schema = null;
2396 } else {
2397 list( $table ) = $dbDetails;
2398 if ( $wgSharedDB !== null # We have a shared database
2399 && $this->mForeign == false # We're not working on a foreign database
2400 && !$this->isQuotedIdentifier( $table ) # Prevent shared tables listing '`table`'
2401 && in_array( $table, $wgSharedTables ) # A shared table is selected
2402 ) {
2403 $database = $wgSharedDB;
2404 $schema = $wgSharedSchema === null ? $this->mSchema : $wgSharedSchema;
2405 $prefix = $wgSharedPrefix === null ? $this->mTablePrefix : $wgSharedPrefix;
2406 } else {
2407 $database = null;
2408 $schema = $this->mSchema; # Default schema
2409 $prefix = $this->mTablePrefix; # Default prefix
2410 }
2411 }
2412
2413 # Quote $table and apply the prefix if not quoted.
2414 # $tableName might be empty if this is called from Database::replaceVars()
2415 $tableName = "{$prefix}{$table}";
2416 if ( $format == 'quoted' && !$this->isQuotedIdentifier( $tableName ) && $tableName !== '' ) {
2417 $tableName = $this->addIdentifierQuotes( $tableName );
2418 }
2419
2420 # Quote $schema and merge it with the table name if needed
2421 if ( $schema !== null ) {
2422 if ( $format == 'quoted' && !$this->isQuotedIdentifier( $schema ) ) {
2423 $schema = $this->addIdentifierQuotes( $schema );
2424 }
2425 $tableName = $schema . '.' . $tableName;
2426 }
2427
2428 # Quote $database and merge it with the table name if needed
2429 if ( $database !== null ) {
2430 if ( $format == 'quoted' && !$this->isQuotedIdentifier( $database ) ) {
2431 $database = $this->addIdentifierQuotes( $database );
2432 }
2433 $tableName = $database . '.' . $tableName;
2434 }
2435
2436 return $tableName;
2437 }
2438
2439 /**
2440 * Fetch a number of table names into an array
2441 * This is handy when you need to construct SQL for joins
2442 *
2443 * Example:
2444 * extract( $dbr->tableNames( 'user', 'watchlist' ) );
2445 * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
2446 * WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
2447 *
2448 * @return array
2449 */
2450 public function tableNames() {
2451 $inArray = func_get_args();
2452 $retVal = array();
2453
2454 foreach ( $inArray as $name ) {
2455 $retVal[$name] = $this->tableName( $name );
2456 }
2457
2458 return $retVal;
2459 }
2460
2461 /**
2462 * Fetch a number of table names into an zero-indexed numerical array
2463 * This is handy when you need to construct SQL for joins
2464 *
2465 * Example:
2466 * list( $user, $watchlist ) = $dbr->tableNamesN( 'user', 'watchlist' );
2467 * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
2468 * WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
2469 *
2470 * @return array
2471 */
2472 public function tableNamesN() {
2473 $inArray = func_get_args();
2474 $retVal = array();
2475
2476 foreach ( $inArray as $name ) {
2477 $retVal[] = $this->tableName( $name );
2478 }
2479
2480 return $retVal;
2481 }
2482
2483 /**
2484 * Get an aliased table name
2485 * e.g. tableName AS newTableName
2486 *
2487 * @param string $name Table name, see tableName()
2488 * @param string|bool $alias Alias (optional)
2489 * @return string SQL name for aliased table. Will not alias a table to its own name
2490 */
2491 public function tableNameWithAlias( $name, $alias = false ) {
2492 if ( !$alias || $alias == $name ) {
2493 return $this->tableName( $name );
2494 } else {
2495 return $this->tableName( $name ) . ' ' . $this->addIdentifierQuotes( $alias );
2496 }
2497 }
2498
2499 /**
2500 * Gets an array of aliased table names
2501 *
2502 * @param array $tables Array( [alias] => table )
2503 * @return string[] See tableNameWithAlias()
2504 */
2505 public function tableNamesWithAlias( $tables ) {
2506 $retval = array();
2507 foreach ( $tables as $alias => $table ) {
2508 if ( is_numeric( $alias ) ) {
2509 $alias = $table;
2510 }
2511 $retval[] = $this->tableNameWithAlias( $table, $alias );
2512 }
2513
2514 return $retval;
2515 }
2516
2517 /**
2518 * Get an aliased field name
2519 * e.g. fieldName AS newFieldName
2520 *
2521 * @param string $name Field name
2522 * @param string|bool $alias Alias (optional)
2523 * @return string SQL name for aliased field. Will not alias a field to its own name
2524 */
2525 public function fieldNameWithAlias( $name, $alias = false ) {
2526 if ( !$alias || (string)$alias === (string)$name ) {
2527 return $name;
2528 } else {
2529 return $name . ' AS ' . $alias; //PostgreSQL needs AS
2530 }
2531 }
2532
2533 /**
2534 * Gets an array of aliased field names
2535 *
2536 * @param array $fields Array( [alias] => field )
2537 * @return string[] See fieldNameWithAlias()
2538 */
2539 public function fieldNamesWithAlias( $fields ) {
2540 $retval = array();
2541 foreach ( $fields as $alias => $field ) {
2542 if ( is_numeric( $alias ) ) {
2543 $alias = $field;
2544 }
2545 $retval[] = $this->fieldNameWithAlias( $field, $alias );
2546 }
2547
2548 return $retval;
2549 }
2550
2551 /**
2552 * Get the aliased table name clause for a FROM clause
2553 * which might have a JOIN and/or USE INDEX clause
2554 *
2555 * @param array $tables ( [alias] => table )
2556 * @param array $use_index Same as for select()
2557 * @param array $join_conds Same as for select()
2558 * @return string
2559 */
2560 protected function tableNamesWithUseIndexOrJOIN(
2561 $tables, $use_index = array(), $join_conds = array()
2562 ) {
2563 $ret = array();
2564 $retJOIN = array();
2565 $use_index = (array)$use_index;
2566 $join_conds = (array)$join_conds;
2567
2568 foreach ( $tables as $alias => $table ) {
2569 if ( !is_string( $alias ) ) {
2570 // No alias? Set it equal to the table name
2571 $alias = $table;
2572 }
2573 // Is there a JOIN clause for this table?
2574 if ( isset( $join_conds[$alias] ) ) {
2575 list( $joinType, $conds ) = $join_conds[$alias];
2576 $tableClause = $joinType;
2577 $tableClause .= ' ' . $this->tableNameWithAlias( $table, $alias );
2578 if ( isset( $use_index[$alias] ) ) { // has USE INDEX?
2579 $use = $this->useIndexClause( implode( ',', (array)$use_index[$alias] ) );
2580 if ( $use != '' ) {
2581 $tableClause .= ' ' . $use;
2582 }
2583 }
2584 $on = $this->makeList( (array)$conds, LIST_AND );
2585 if ( $on != '' ) {
2586 $tableClause .= ' ON (' . $on . ')';
2587 }
2588
2589 $retJOIN[] = $tableClause;
2590 } elseif ( isset( $use_index[$alias] ) ) {
2591 // Is there an INDEX clause for this table?
2592 $tableClause = $this->tableNameWithAlias( $table, $alias );
2593 $tableClause .= ' ' . $this->useIndexClause(
2594 implode( ',', (array)$use_index[$alias] )
2595 );
2596
2597 $ret[] = $tableClause;
2598 } else {
2599 $tableClause = $this->tableNameWithAlias( $table, $alias );
2600
2601 $ret[] = $tableClause;
2602 }
2603 }
2604
2605 // We can't separate explicit JOIN clauses with ',', use ' ' for those
2606 $implicitJoins = !empty( $ret ) ? implode( ',', $ret ) : "";
2607 $explicitJoins = !empty( $retJOIN ) ? implode( ' ', $retJOIN ) : "";
2608
2609 // Compile our final table clause
2610 return implode( ' ', array( $implicitJoins, $explicitJoins ) );
2611 }
2612
2613 /**
2614 * Get the name of an index in a given table.
2615 *
2616 * @protected Don't use outside of DatabaseBase and childs
2617 * @param string $index
2618 * @return string
2619 */
2620 public function indexName( $index ) {
2621 // @FIXME: Make this protected once we move away from PHP 5.3
2622 // Needs to be public because of usage in closure (in DatabaseBase::replaceVars)
2623
2624 // Backwards-compatibility hack
2625 $renamed = array(
2626 'ar_usertext_timestamp' => 'usertext_timestamp',
2627 'un_user_id' => 'user_id',
2628 'un_user_ip' => 'user_ip',
2629 );
2630
2631 if ( isset( $renamed[$index] ) ) {
2632 return $renamed[$index];
2633 } else {
2634 return $index;
2635 }
2636 }
2637
2638 /**
2639 * Adds quotes and backslashes.
2640 *
2641 * @param string $s
2642 * @return string
2643 */
2644 public function addQuotes( $s ) {
2645 if ( $s === null ) {
2646 return 'NULL';
2647 } else {
2648 # This will also quote numeric values. This should be harmless,
2649 # and protects against weird problems that occur when they really
2650 # _are_ strings such as article titles and string->number->string
2651 # conversion is not 1:1.
2652 return "'" . $this->strencode( $s ) . "'";
2653 }
2654 }
2655
2656 /**
2657 * Quotes an identifier using `backticks` or "double quotes" depending on the database type.
2658 * MySQL uses `backticks` while basically everything else uses double quotes.
2659 * Since MySQL is the odd one out here the double quotes are our generic
2660 * and we implement backticks in DatabaseMysql.
2661 *
2662 * @param string $s
2663 * @return string
2664 */
2665 public function addIdentifierQuotes( $s ) {
2666 return '"' . str_replace( '"', '""', $s ) . '"';
2667 }
2668
2669 /**
2670 * Returns if the given identifier looks quoted or not according to
2671 * the database convention for quoting identifiers .
2672 *
2673 * @param string $name
2674 * @return bool
2675 */
2676 public function isQuotedIdentifier( $name ) {
2677 return $name[0] == '"' && substr( $name, -1, 1 ) == '"';
2678 }
2679
2680 /**
2681 * @param string $s
2682 * @return string
2683 */
2684 protected function escapeLikeInternal( $s ) {
2685 return addcslashes( $s, '\%_' );
2686 }
2687
2688 /**
2689 * LIKE statement wrapper, receives a variable-length argument list with
2690 * parts of pattern to match containing either string literals that will be
2691 * escaped or tokens returned by anyChar() or anyString(). Alternatively,
2692 * the function could be provided with an array of aforementioned
2693 * parameters.
2694 *
2695 * Example: $dbr->buildLike( 'My_page_title/', $dbr->anyString() ) returns
2696 * a LIKE clause that searches for subpages of 'My page title'.
2697 * Alternatively:
2698 * $pattern = array( 'My_page_title/', $dbr->anyString() );
2699 * $query .= $dbr->buildLike( $pattern );
2700 *
2701 * @since 1.16
2702 * @return string Fully built LIKE statement
2703 */
2704 public function buildLike() {
2705 $params = func_get_args();
2706
2707 if ( count( $params ) > 0 && is_array( $params[0] ) ) {
2708 $params = $params[0];
2709 }
2710
2711 $s = '';
2712
2713 foreach ( $params as $value ) {
2714 if ( $value instanceof LikeMatch ) {
2715 $s .= $value->toString();
2716 } else {
2717 $s .= $this->escapeLikeInternal( $value );
2718 }
2719 }
2720
2721 return " LIKE {$this->addQuotes( $s )} ";
2722 }
2723
2724 /**
2725 * Returns a token for buildLike() that denotes a '_' to be used in a LIKE query
2726 *
2727 * @return LikeMatch
2728 */
2729 public function anyChar() {
2730 return new LikeMatch( '_' );
2731 }
2732
2733 /**
2734 * Returns a token for buildLike() that denotes a '%' to be used in a LIKE query
2735 *
2736 * @return LikeMatch
2737 */
2738 public function anyString() {
2739 return new LikeMatch( '%' );
2740 }
2741
2742 /**
2743 * Returns an appropriately quoted sequence value for inserting a new row.
2744 * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
2745 * subclass will return an integer, and save the value for insertId()
2746 *
2747 * Any implementation of this function should *not* involve reusing
2748 * sequence numbers created for rolled-back transactions.
2749 * See http://bugs.mysql.com/bug.php?id=30767 for details.
2750 * @param string $seqName
2751 * @return null|int
2752 */
2753 public function nextSequenceValue( $seqName ) {
2754 return null;
2755 }
2756
2757 /**
2758 * USE INDEX clause. Unlikely to be useful for anything but MySQL. This
2759 * is only needed because a) MySQL must be as efficient as possible due to
2760 * its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about
2761 * which index to pick. Anyway, other databases might have different
2762 * indexes on a given table. So don't bother overriding this unless you're
2763 * MySQL.
2764 * @param string $index
2765 * @return string
2766 */
2767 public function useIndexClause( $index ) {
2768 return '';
2769 }
2770
2771 /**
2772 * REPLACE query wrapper.
2773 *
2774 * REPLACE is a very handy MySQL extension, which functions like an INSERT
2775 * except that when there is a duplicate key error, the old row is deleted
2776 * and the new row is inserted in its place.
2777 *
2778 * We simulate this with standard SQL with a DELETE followed by INSERT. To
2779 * perform the delete, we need to know what the unique indexes are so that
2780 * we know how to find the conflicting rows.
2781 *
2782 * It may be more efficient to leave off unique indexes which are unlikely
2783 * to collide. However if you do this, you run the risk of encountering
2784 * errors which wouldn't have occurred in MySQL.
2785 *
2786 * @param string $table The table to replace the row(s) in.
2787 * @param array $uniqueIndexes Is an array of indexes. Each element may be either
2788 * a field name or an array of field names
2789 * @param array $rows Can be either a single row to insert, or multiple rows,
2790 * in the same format as for DatabaseBase::insert()
2791 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
2792 */
2793 public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
2794 $quotedTable = $this->tableName( $table );
2795
2796 if ( count( $rows ) == 0 ) {
2797 return;
2798 }
2799
2800 # Single row case
2801 if ( !is_array( reset( $rows ) ) ) {
2802 $rows = array( $rows );
2803 }
2804
2805 foreach ( $rows as $row ) {
2806 # Delete rows which collide
2807 if ( $uniqueIndexes ) {
2808 $sql = "DELETE FROM $quotedTable WHERE ";
2809 $first = true;
2810 foreach ( $uniqueIndexes as $index ) {
2811 if ( $first ) {
2812 $first = false;
2813 $sql .= '( ';
2814 } else {
2815 $sql .= ' ) OR ( ';
2816 }
2817 if ( is_array( $index ) ) {
2818 $first2 = true;
2819 foreach ( $index as $col ) {
2820 if ( $first2 ) {
2821 $first2 = false;
2822 } else {
2823 $sql .= ' AND ';
2824 }
2825 $sql .= $col . '=' . $this->addQuotes( $row[$col] );
2826 }
2827 } else {
2828 $sql .= $index . '=' . $this->addQuotes( $row[$index] );
2829 }
2830 }
2831 $sql .= ' )';
2832 $this->query( $sql, $fname );
2833 }
2834
2835 # Now insert the row
2836 $this->insert( $table, $row, $fname );
2837 }
2838 }
2839
2840 /**
2841 * REPLACE query wrapper for MySQL and SQLite, which have a native REPLACE
2842 * statement.
2843 *
2844 * @param string $table Table name
2845 * @param array|string $rows Row(s) to insert
2846 * @param string $fname Caller function name
2847 *
2848 * @return ResultWrapper
2849 */
2850 protected function nativeReplace( $table, $rows, $fname ) {
2851 $table = $this->tableName( $table );
2852
2853 # Single row case
2854 if ( !is_array( reset( $rows ) ) ) {
2855 $rows = array( $rows );
2856 }
2857
2858 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) . ') VALUES ';
2859 $first = true;
2860
2861 foreach ( $rows as $row ) {
2862 if ( $first ) {
2863 $first = false;
2864 } else {
2865 $sql .= ',';
2866 }
2867
2868 $sql .= '(' . $this->makeList( $row ) . ')';
2869 }
2870
2871 return $this->query( $sql, $fname );
2872 }
2873
2874 /**
2875 * INSERT ON DUPLICATE KEY UPDATE wrapper, upserts an array into a table.
2876 *
2877 * This updates any conflicting rows (according to the unique indexes) using
2878 * the provided SET clause and inserts any remaining (non-conflicted) rows.
2879 *
2880 * $rows may be either:
2881 * - A single associative array. The array keys are the field names, and
2882 * the values are the values to insert. The values are treated as data
2883 * and will be quoted appropriately. If NULL is inserted, this will be
2884 * converted to a database NULL.
2885 * - An array with numeric keys, holding a list of associative arrays.
2886 * This causes a multi-row INSERT on DBMSs that support it. The keys in
2887 * each subarray must be identical to each other, and in the same order.
2888 *
2889 * It may be more efficient to leave off unique indexes which are unlikely
2890 * to collide. However if you do this, you run the risk of encountering
2891 * errors which wouldn't have occurred in MySQL.
2892 *
2893 * Usually throws a DBQueryError on failure. If errors are explicitly ignored,
2894 * returns success.
2895 *
2896 * @since 1.22
2897 *
2898 * @param string $table Table name. This will be passed through DatabaseBase::tableName().
2899 * @param array $rows A single row or list of rows to insert
2900 * @param array $uniqueIndexes List of single field names or field name tuples
2901 * @param array $set An array of values to SET. For each array element, the
2902 * key gives the field name, and the value gives the data to set that
2903 * field to. The data will be quoted by DatabaseBase::addQuotes().
2904 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
2905 * @throws Exception
2906 * @return bool
2907 */
2908 public function upsert( $table, array $rows, array $uniqueIndexes, array $set,
2909 $fname = __METHOD__
2910 ) {
2911 if ( !count( $rows ) ) {
2912 return true; // nothing to do
2913 }
2914
2915 if ( !is_array( reset( $rows ) ) ) {
2916 $rows = array( $rows );
2917 }
2918
2919 if ( count( $uniqueIndexes ) ) {
2920 $clauses = array(); // list WHERE clauses that each identify a single row
2921 foreach ( $rows as $row ) {
2922 foreach ( $uniqueIndexes as $index ) {
2923 $index = is_array( $index ) ? $index : array( $index ); // columns
2924 $rowKey = array(); // unique key to this row
2925 foreach ( $index as $column ) {
2926 $rowKey[$column] = $row[$column];
2927 }
2928 $clauses[] = $this->makeList( $rowKey, LIST_AND );
2929 }
2930 }
2931 $where = array( $this->makeList( $clauses, LIST_OR ) );
2932 } else {
2933 $where = false;
2934 }
2935
2936 $useTrx = !$this->mTrxLevel;
2937 if ( $useTrx ) {
2938 $this->begin( $fname );
2939 }
2940 try {
2941 # Update any existing conflicting row(s)
2942 if ( $where !== false ) {
2943 $ok = $this->update( $table, $set, $where, $fname );
2944 } else {
2945 $ok = true;
2946 }
2947 # Now insert any non-conflicting row(s)
2948 $ok = $this->insert( $table, $rows, $fname, array( 'IGNORE' ) ) && $ok;
2949 } catch ( Exception $e ) {
2950 if ( $useTrx ) {
2951 $this->rollback( $fname );
2952 }
2953 throw $e;
2954 }
2955 if ( $useTrx ) {
2956 $this->commit( $fname );
2957 }
2958
2959 return $ok;
2960 }
2961
2962 /**
2963 * DELETE where the condition is a join.
2964 *
2965 * MySQL overrides this to use a multi-table DELETE syntax, in other databases
2966 * we use sub-selects
2967 *
2968 * For safety, an empty $conds will not delete everything. If you want to
2969 * delete all rows where the join condition matches, set $conds='*'.
2970 *
2971 * DO NOT put the join condition in $conds.
2972 *
2973 * @param string $delTable The table to delete from.
2974 * @param string $joinTable The other table.
2975 * @param string $delVar The variable to join on, in the first table.
2976 * @param string $joinVar The variable to join on, in the second table.
2977 * @param array $conds Condition array of field names mapped to variables,
2978 * ANDed together in the WHERE clause
2979 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
2980 * @throws DBUnexpectedError
2981 */
2982 public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
2983 $fname = __METHOD__
2984 ) {
2985 if ( !$conds ) {
2986 throw new DBUnexpectedError( $this,
2987 'DatabaseBase::deleteJoin() called with empty $conds' );
2988 }
2989
2990 $delTable = $this->tableName( $delTable );
2991 $joinTable = $this->tableName( $joinTable );
2992 $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
2993 if ( $conds != '*' ) {
2994 $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
2995 }
2996 $sql .= ')';
2997
2998 $this->query( $sql, $fname );
2999 }
3000
3001 /**
3002 * Returns the size of a text field, or -1 for "unlimited"
3003 *
3004 * @param string $table
3005 * @param string $field
3006 * @return int
3007 */
3008 public function textFieldSize( $table, $field ) {
3009 $table = $this->tableName( $table );
3010 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
3011 $res = $this->query( $sql, 'DatabaseBase::textFieldSize' );
3012 $row = $this->fetchObject( $res );
3013
3014 $m = array();
3015
3016 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
3017 $size = $m[1];
3018 } else {
3019 $size = -1;
3020 }
3021
3022 return $size;
3023 }
3024
3025 /**
3026 * A string to insert into queries to show that they're low-priority, like
3027 * MySQL's LOW_PRIORITY. If no such feature exists, return an empty
3028 * string and nothing bad should happen.
3029 *
3030 * @return string Returns the text of the low priority option if it is
3031 * supported, or a blank string otherwise
3032 */
3033 public function lowPriorityOption() {
3034 return '';
3035 }
3036
3037 /**
3038 * DELETE query wrapper.
3039 *
3040 * @param array $table Table name
3041 * @param string|array $conds Array of conditions. See $conds in DatabaseBase::select()
3042 * for the format. Use $conds == "*" to delete all rows
3043 * @param string $fname Name of the calling function
3044 * @throws DBUnexpectedError
3045 * @return bool|ResultWrapper
3046 */
3047 public function delete( $table, $conds, $fname = __METHOD__ ) {
3048 if ( !$conds ) {
3049 throw new DBUnexpectedError( $this, 'DatabaseBase::delete() called with no conditions' );
3050 }
3051
3052 $table = $this->tableName( $table );
3053 $sql = "DELETE FROM $table";
3054
3055 if ( $conds != '*' ) {
3056 if ( is_array( $conds ) ) {
3057 $conds = $this->makeList( $conds, LIST_AND );
3058 }
3059 $sql .= ' WHERE ' . $conds;
3060 }
3061
3062 return $this->query( $sql, $fname );
3063 }
3064
3065 /**
3066 * INSERT SELECT wrapper. Takes data from a SELECT query and inserts it
3067 * into another table.
3068 *
3069 * @param string $destTable The table name to insert into
3070 * @param string|array $srcTable May be either a table name, or an array of table names
3071 * to include in a join.
3072 *
3073 * @param array $varMap Must be an associative array of the form
3074 * array( 'dest1' => 'source1', ...). Source items may be literals
3075 * rather than field names, but strings should be quoted with
3076 * DatabaseBase::addQuotes()
3077 *
3078 * @param array $conds Condition array. See $conds in DatabaseBase::select() for
3079 * the details of the format of condition arrays. May be "*" to copy the
3080 * whole table.
3081 *
3082 * @param string $fname The function name of the caller, from __METHOD__
3083 *
3084 * @param array $insertOptions Options for the INSERT part of the query, see
3085 * DatabaseBase::insert() for details.
3086 * @param array $selectOptions Options for the SELECT part of the query, see
3087 * DatabaseBase::select() for details.
3088 *
3089 * @return ResultWrapper
3090 */
3091 public function insertSelect( $destTable, $srcTable, $varMap, $conds,
3092 $fname = __METHOD__,
3093 $insertOptions = array(), $selectOptions = array()
3094 ) {
3095 $destTable = $this->tableName( $destTable );
3096
3097 if ( !is_array( $insertOptions ) ) {
3098 $insertOptions = array( $insertOptions );
3099 }
3100
3101 $insertOptions = $this->makeInsertOptions( $insertOptions );
3102
3103 if ( !is_array( $selectOptions ) ) {
3104 $selectOptions = array( $selectOptions );
3105 }
3106
3107 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
3108
3109 if ( is_array( $srcTable ) ) {
3110 $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
3111 } else {
3112 $srcTable = $this->tableName( $srcTable );
3113 }
3114
3115 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
3116 " SELECT $startOpts " . implode( ',', $varMap ) .
3117 " FROM $srcTable $useIndex ";
3118
3119 if ( $conds != '*' ) {
3120 if ( is_array( $conds ) ) {
3121 $conds = $this->makeList( $conds, LIST_AND );
3122 }
3123 $sql .= " WHERE $conds";
3124 }
3125
3126 $sql .= " $tailOpts";
3127
3128 return $this->query( $sql, $fname );
3129 }
3130
3131 /**
3132 * Construct a LIMIT query with optional offset. This is used for query
3133 * pages. The SQL should be adjusted so that only the first $limit rows
3134 * are returned. If $offset is provided as well, then the first $offset
3135 * rows should be discarded, and the next $limit rows should be returned.
3136 * If the result of the query is not ordered, then the rows to be returned
3137 * are theoretically arbitrary.
3138 *
3139 * $sql is expected to be a SELECT, if that makes a difference.
3140 *
3141 * The version provided by default works in MySQL and SQLite. It will very
3142 * likely need to be overridden for most other DBMSes.
3143 *
3144 * @param string $sql SQL query we will append the limit too
3145 * @param int $limit The SQL limit
3146 * @param int|bool $offset The SQL offset (default false)
3147 * @throws DBUnexpectedError
3148 * @return string
3149 */
3150 public function limitResult( $sql, $limit, $offset = false ) {
3151 if ( !is_numeric( $limit ) ) {
3152 throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
3153 }
3154
3155 return "$sql LIMIT "
3156 . ( ( is_numeric( $offset ) && $offset != 0 ) ? "{$offset}," : "" )
3157 . "{$limit} ";
3158 }
3159
3160 /**
3161 * Returns true if current database backend supports ORDER BY or LIMIT for separate subqueries
3162 * within the UNION construct.
3163 * @return bool
3164 */
3165 public function unionSupportsOrderAndLimit() {
3166 return true; // True for almost every DB supported
3167 }
3168
3169 /**
3170 * Construct a UNION query
3171 * This is used for providing overload point for other DB abstractions
3172 * not compatible with the MySQL syntax.
3173 * @param array $sqls SQL statements to combine
3174 * @param bool $all Use UNION ALL
3175 * @return string SQL fragment
3176 */
3177 public function unionQueries( $sqls, $all ) {
3178 $glue = $all ? ') UNION ALL (' : ') UNION (';
3179
3180 return '(' . implode( $glue, $sqls ) . ')';
3181 }
3182
3183 /**
3184 * Returns an SQL expression for a simple conditional. This doesn't need
3185 * to be overridden unless CASE isn't supported in your DBMS.
3186 *
3187 * @param string|array $cond SQL expression which will result in a boolean value
3188 * @param string $trueVal SQL expression to return if true
3189 * @param string $falseVal SQL expression to return if false
3190 * @return string SQL fragment
3191 */
3192 public function conditional( $cond, $trueVal, $falseVal ) {
3193 if ( is_array( $cond ) ) {
3194 $cond = $this->makeList( $cond, LIST_AND );
3195 }
3196
3197 return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
3198 }
3199
3200 /**
3201 * Returns a comand for str_replace function in SQL query.
3202 * Uses REPLACE() in MySQL
3203 *
3204 * @param string $orig Column to modify
3205 * @param string $old Column to seek
3206 * @param string $new Column to replace with
3207 *
3208 * @return string
3209 */
3210 public function strreplace( $orig, $old, $new ) {
3211 return "REPLACE({$orig}, {$old}, {$new})";
3212 }
3213
3214 /**
3215 * Determines how long the server has been up
3216 * STUB
3217 *
3218 * @return int
3219 */
3220 public function getServerUptime() {
3221 return 0;
3222 }
3223
3224 /**
3225 * Determines if the last failure was due to a deadlock
3226 * STUB
3227 *
3228 * @return bool
3229 */
3230 public function wasDeadlock() {
3231 return false;
3232 }
3233
3234 /**
3235 * Determines if the last failure was due to a lock timeout
3236 * STUB
3237 *
3238 * @return bool
3239 */
3240 public function wasLockTimeout() {
3241 return false;
3242 }
3243
3244 /**
3245 * Determines if the last query error was something that should be dealt
3246 * with by pinging the connection and reissuing the query.
3247 * STUB
3248 *
3249 * @return bool
3250 */
3251 public function wasErrorReissuable() {
3252 return false;
3253 }
3254
3255 /**
3256 * Determines if the last failure was due to the database being read-only.
3257 * STUB
3258 *
3259 * @return bool
3260 */
3261 public function wasReadOnlyError() {
3262 return false;
3263 }
3264
3265 /**
3266 * Perform a deadlock-prone transaction.
3267 *
3268 * This function invokes a callback function to perform a set of write
3269 * queries. If a deadlock occurs during the processing, the transaction
3270 * will be rolled back and the callback function will be called again.
3271 *
3272 * Usage:
3273 * $dbw->deadlockLoop( callback, ... );
3274 *
3275 * Extra arguments are passed through to the specified callback function.
3276 *
3277 * Returns whatever the callback function returned on its successful,
3278 * iteration, or false on error, for example if the retry limit was
3279 * reached.
3280 *
3281 * @return bool
3282 */
3283 public function deadlockLoop() {
3284 $this->begin( __METHOD__ );
3285 $args = func_get_args();
3286 $function = array_shift( $args );
3287 $oldIgnore = $this->ignoreErrors( true );
3288 $tries = self::DEADLOCK_TRIES;
3289
3290 if ( is_array( $function ) ) {
3291 $fname = $function[0];
3292 } else {
3293 $fname = $function;
3294 }
3295
3296 do {
3297 $retVal = call_user_func_array( $function, $args );
3298 $error = $this->lastError();
3299 $errno = $this->lastErrno();
3300 $sql = $this->lastQuery();
3301
3302 if ( $errno ) {
3303 if ( $this->wasDeadlock() ) {
3304 # Retry
3305 usleep( mt_rand( self::DEADLOCK_DELAY_MIN, self::DEADLOCK_DELAY_MAX ) );
3306 } else {
3307 $this->reportQueryError( $error, $errno, $sql, $fname );
3308 }
3309 }
3310 } while ( $this->wasDeadlock() && --$tries > 0 );
3311
3312 $this->ignoreErrors( $oldIgnore );
3313
3314 if ( $tries <= 0 ) {
3315 $this->rollback( __METHOD__ );
3316 $this->reportQueryError( $error, $errno, $sql, $fname );
3317
3318 return false;
3319 } else {
3320 $this->commit( __METHOD__ );
3321
3322 return $retVal;
3323 }
3324 }
3325
3326 /**
3327 * Wait for the slave to catch up to a given master position.
3328 *
3329 * @param DBMasterPos $pos
3330 * @param int $timeout The maximum number of seconds to wait for
3331 * synchronisation
3332 * @return int Zero if the slave was past that position already,
3333 * greater than zero if we waited for some period of time, less than
3334 * zero if we timed out.
3335 */
3336 public function masterPosWait( DBMasterPos $pos, $timeout ) {
3337 # Real waits are implemented in the subclass.
3338 return 0;
3339 }
3340
3341 /**
3342 * Get the replication position of this slave
3343 *
3344 * @return DBMasterPos|bool False if this is not a slave.
3345 */
3346 public function getSlavePos() {
3347 # Stub
3348 return false;
3349 }
3350
3351 /**
3352 * Get the position of this master
3353 *
3354 * @return DBMasterPos|bool False if this is not a master
3355 */
3356 public function getMasterPos() {
3357 # Stub
3358 return false;
3359 }
3360
3361 /**
3362 * Run an anonymous function as soon as there is no transaction pending.
3363 * If there is a transaction and it is rolled back, then the callback is cancelled.
3364 * Queries in the function will run in AUTO-COMMIT mode unless there are begin() calls.
3365 * Callbacks must commit any transactions that they begin.
3366 *
3367 * This is useful for updates to different systems or when separate transactions are needed.
3368 * For example, one might want to enqueue jobs into a system outside the database, but only
3369 * after the database is updated so that the jobs will see the data when they actually run.
3370 * It can also be used for updates that easily cause deadlocks if locks are held too long.
3371 *
3372 * @param callable $callback
3373 * @since 1.20
3374 */
3375 final public function onTransactionIdle( $callback ) {
3376 $this->mTrxIdleCallbacks[] = array( $callback, wfGetCaller() );
3377 if ( !$this->mTrxLevel ) {
3378 $this->runOnTransactionIdleCallbacks();
3379 }
3380 }
3381
3382 /**
3383 * Run an anonymous function before the current transaction commits or now if there is none.
3384 * If there is a transaction and it is rolled back, then the callback is cancelled.
3385 * Callbacks must not start nor commit any transactions.
3386 *
3387 * This is useful for updates that easily cause deadlocks if locks are held too long
3388 * but where atomicity is strongly desired for these updates and some related updates.
3389 *
3390 * @param callable $callback
3391 * @since 1.22
3392 */
3393 final public function onTransactionPreCommitOrIdle( $callback ) {
3394 if ( $this->mTrxLevel ) {
3395 $this->mTrxPreCommitCallbacks[] = array( $callback, wfGetCaller() );
3396 } else {
3397 $this->onTransactionIdle( $callback ); // this will trigger immediately
3398 }
3399 }
3400
3401 /**
3402 * Actually any "on transaction idle" callbacks.
3403 *
3404 * @since 1.20
3405 */
3406 protected function runOnTransactionIdleCallbacks() {
3407 $autoTrx = $this->getFlag( DBO_TRX ); // automatic begin() enabled?
3408
3409 $e = $ePrior = null; // last exception
3410 do { // callbacks may add callbacks :)
3411 $callbacks = $this->mTrxIdleCallbacks;
3412 $this->mTrxIdleCallbacks = array(); // recursion guard
3413 foreach ( $callbacks as $callback ) {
3414 try {
3415 list( $phpCallback ) = $callback;
3416 $this->clearFlag( DBO_TRX ); // make each query its own transaction
3417 call_user_func( $phpCallback );
3418 $this->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore automatic begin()
3419 } catch ( Exception $e ) {
3420 if ( $ePrior ) {
3421 MWExceptionHandler::logException( $ePrior );
3422 }
3423 $ePrior = $e;
3424 }
3425 }
3426 } while ( count( $this->mTrxIdleCallbacks ) );
3427
3428 if ( $e instanceof Exception ) {
3429 throw $e; // re-throw any last exception
3430 }
3431 }
3432
3433 /**
3434 * Actually any "on transaction pre-commit" callbacks.
3435 *
3436 * @since 1.22
3437 */
3438 protected function runOnTransactionPreCommitCallbacks() {
3439 $e = $ePrior = null; // last exception
3440 do { // callbacks may add callbacks :)
3441 $callbacks = $this->mTrxPreCommitCallbacks;
3442 $this->mTrxPreCommitCallbacks = array(); // recursion guard
3443 foreach ( $callbacks as $callback ) {
3444 try {
3445 list( $phpCallback ) = $callback;
3446 call_user_func( $phpCallback );
3447 } catch ( Exception $e ) {
3448 if ( $ePrior ) {
3449 MWExceptionHandler::logException( $ePrior );
3450 }
3451 $ePrior = $e;
3452 }
3453 }
3454 } while ( count( $this->mTrxPreCommitCallbacks ) );
3455
3456 if ( $e instanceof Exception ) {
3457 throw $e; // re-throw any last exception
3458 }
3459 }
3460
3461 /**
3462 * Begin an atomic section of statements
3463 *
3464 * If a transaction has been started already, just keep track of the given
3465 * section name to make sure the transaction is not committed pre-maturely.
3466 * This function can be used in layers (with sub-sections), so use a stack
3467 * to keep track of the different atomic sections. If there is no transaction,
3468 * start one implicitly.
3469 *
3470 * The goal of this function is to create an atomic section of SQL queries
3471 * without having to start a new transaction if it already exists.
3472 *
3473 * Atomic sections are more strict than transactions. With transactions,
3474 * attempting to begin a new transaction when one is already running results
3475 * in MediaWiki issuing a brief warning and doing an implicit commit. All
3476 * atomic levels *must* be explicitly closed using DatabaseBase::endAtomic(),
3477 * and any database transactions cannot be began or committed until all atomic
3478 * levels are closed. There is no such thing as implicitly opening or closing
3479 * an atomic section.
3480 *
3481 * @since 1.23
3482 * @param string $fname
3483 * @throws DBError
3484 */
3485 final public function startAtomic( $fname = __METHOD__ ) {
3486 if ( !$this->mTrxLevel ) {
3487 $this->begin( $fname );
3488 $this->mTrxAutomatic = true;
3489 $this->mTrxAutomaticAtomic = true;
3490 }
3491
3492 $this->mTrxAtomicLevels->push( $fname );
3493 }
3494
3495 /**
3496 * Ends an atomic section of SQL statements
3497 *
3498 * Ends the next section of atomic SQL statements and commits the transaction
3499 * if necessary.
3500 *
3501 * @since 1.23
3502 * @see DatabaseBase::startAtomic
3503 * @param string $fname
3504 * @throws DBError
3505 */
3506 final public function endAtomic( $fname = __METHOD__ ) {
3507 if ( !$this->mTrxLevel ) {
3508 throw new DBUnexpectedError( $this, 'No atomic transaction is open.' );
3509 }
3510 if ( $this->mTrxAtomicLevels->isEmpty() ||
3511 $this->mTrxAtomicLevels->pop() !== $fname
3512 ) {
3513 throw new DBUnexpectedError( $this, 'Invalid atomic section ended.' );
3514 }
3515
3516 if ( $this->mTrxAtomicLevels->isEmpty() && $this->mTrxAutomaticAtomic ) {
3517 $this->commit( $fname, 'flush' );
3518 }
3519 }
3520
3521 /**
3522 * Begin a transaction. If a transaction is already in progress,
3523 * that transaction will be committed before the new transaction is started.
3524 *
3525 * Note that when the DBO_TRX flag is set (which is usually the case for web
3526 * requests, but not for maintenance scripts), any previous database query
3527 * will have started a transaction automatically.
3528 *
3529 * Nesting of transactions is not supported. Attempts to nest transactions
3530 * will cause a warning, unless the current transaction was started
3531 * automatically because of the DBO_TRX flag.
3532 *
3533 * @param string $fname
3534 * @throws DBError
3535 */
3536 final public function begin( $fname = __METHOD__ ) {
3537 global $wgDebugDBTransactions;
3538
3539 if ( $this->mTrxLevel ) { // implicit commit
3540 if ( !$this->mTrxAtomicLevels->isEmpty() ) {
3541 // If the current transaction was an automatic atomic one, then we definitely have
3542 // a problem. Same if there is any unclosed atomic level.
3543 throw new DBUnexpectedError( $this,
3544 "Attempted to start explicit transaction when atomic levels are still open."
3545 );
3546 } elseif ( !$this->mTrxAutomatic ) {
3547 // We want to warn about inadvertently nested begin/commit pairs, but not about
3548 // auto-committing implicit transactions that were started by query() via DBO_TRX
3549 $msg = "$fname: Transaction already in progress (from {$this->mTrxFname}), " .
3550 " performing implicit commit!";
3551 wfWarn( $msg );
3552 wfLogDBError( $msg,
3553 $this->getLogContext( array(
3554 'method' => __METHOD__,
3555 'fname' => $fname,
3556 ) )
3557 );
3558 } else {
3559 // if the transaction was automatic and has done write operations,
3560 // log it if $wgDebugDBTransactions is enabled.
3561 if ( $this->mTrxDoneWrites && $wgDebugDBTransactions ) {
3562 wfDebug( "$fname: Automatic transaction with writes in progress" .
3563 " (from {$this->mTrxFname}), performing implicit commit!\n"
3564 );
3565 }
3566 }
3567
3568 $this->runOnTransactionPreCommitCallbacks();
3569 $this->doCommit( $fname );
3570 if ( $this->mTrxDoneWrites ) {
3571 Profiler::instance()->getTransactionProfiler()->transactionWritingOut(
3572 $this->mServer, $this->mDBname, $this->mTrxShortId );
3573 }
3574 $this->runOnTransactionIdleCallbacks();
3575 }
3576
3577 # Avoid fatals if close() was called
3578 if ( !$this->isOpen() ) {
3579 throw new DBUnexpectedError( $this, "DB connection was already closed." );
3580 }
3581
3582 $this->doBegin( $fname );
3583 $this->mTrxTimestamp = microtime( true );
3584 $this->mTrxFname = $fname;
3585 $this->mTrxDoneWrites = false;
3586 $this->mTrxAutomatic = false;
3587 $this->mTrxAutomaticAtomic = false;
3588 $this->mTrxAtomicLevels = new SplStack;
3589 $this->mTrxIdleCallbacks = array();
3590 $this->mTrxPreCommitCallbacks = array();
3591 $this->mTrxShortId = wfRandomString( 12 );
3592 }
3593
3594 /**
3595 * Issues the BEGIN command to the database server.
3596 *
3597 * @see DatabaseBase::begin()
3598 * @param string $fname
3599 */
3600 protected function doBegin( $fname ) {
3601 $this->query( 'BEGIN', $fname );
3602 $this->mTrxLevel = 1;
3603 }
3604
3605 /**
3606 * Commits a transaction previously started using begin().
3607 * If no transaction is in progress, a warning is issued.
3608 *
3609 * Nesting of transactions is not supported.
3610 *
3611 * @param string $fname
3612 * @param string $flush Flush flag, set to 'flush' to disable warnings about
3613 * explicitly committing implicit transactions, or calling commit when no
3614 * transaction is in progress. This will silently break any ongoing
3615 * explicit transaction. Only set the flush flag if you are sure that it
3616 * is safe to ignore these warnings in your context.
3617 * @throws DBUnexpectedError
3618 */
3619 final public function commit( $fname = __METHOD__, $flush = '' ) {
3620 if ( !$this->mTrxAtomicLevels->isEmpty() ) {
3621 // There are still atomic sections open. This cannot be ignored
3622 throw new DBUnexpectedError(
3623 $this,
3624 "Attempted to commit transaction while atomic sections are still open"
3625 );
3626 }
3627
3628 if ( $flush === 'flush' ) {
3629 if ( !$this->mTrxLevel ) {
3630 return; // nothing to do
3631 } elseif ( !$this->mTrxAutomatic ) {
3632 wfWarn( "$fname: Flushing an explicit transaction, getting out of sync!" );
3633 }
3634 } else {
3635 if ( !$this->mTrxLevel ) {
3636 wfWarn( "$fname: No transaction to commit, something got out of sync!" );
3637 return; // nothing to do
3638 } elseif ( $this->mTrxAutomatic ) {
3639 wfWarn( "$fname: Explicit commit of implicit transaction. Something may be out of sync!" );
3640 }
3641 }
3642
3643 # Avoid fatals if close() was called
3644 if ( !$this->isOpen() ) {
3645 throw new DBUnexpectedError( $this, "DB connection was already closed." );
3646 }
3647
3648 $this->runOnTransactionPreCommitCallbacks();
3649 $this->doCommit( $fname );
3650 if ( $this->mTrxDoneWrites ) {
3651 Profiler::instance()->getTransactionProfiler()->transactionWritingOut(
3652 $this->mServer, $this->mDBname, $this->mTrxShortId );
3653 }
3654 $this->runOnTransactionIdleCallbacks();
3655 }
3656
3657 /**
3658 * Issues the COMMIT command to the database server.
3659 *
3660 * @see DatabaseBase::commit()
3661 * @param string $fname
3662 */
3663 protected function doCommit( $fname ) {
3664 if ( $this->mTrxLevel ) {
3665 $this->query( 'COMMIT', $fname );
3666 $this->mTrxLevel = 0;
3667 }
3668 }
3669
3670 /**
3671 * Rollback a transaction previously started using begin().
3672 * If no transaction is in progress, a warning is issued.
3673 *
3674 * No-op on non-transactional databases.
3675 *
3676 * @param string $fname
3677 * @param string $flush Flush flag, set to 'flush' to disable warnings about
3678 * calling rollback when no transaction is in progress. This will silently
3679 * break any ongoing explicit transaction. Only set the flush flag if you
3680 * are sure that it is safe to ignore these warnings in your context.
3681 * @throws DBUnexpectedError
3682 * @since 1.23 Added $flush parameter
3683 */
3684 final public function rollback( $fname = __METHOD__, $flush = '' ) {
3685 if ( $flush !== 'flush' ) {
3686 if ( !$this->mTrxLevel ) {
3687 wfWarn( "$fname: No transaction to rollback, something got out of sync!" );
3688 return; // nothing to do
3689 } elseif ( $this->mTrxAutomatic ) {
3690 wfWarn( "$fname: Explicit rollback of implicit transaction. Something may be out of sync!" );
3691 }
3692 } else {
3693 if ( !$this->mTrxLevel ) {
3694 return; // nothing to do
3695 } elseif ( !$this->mTrxAutomatic ) {
3696 wfWarn( "$fname: Flushing an explicit transaction, getting out of sync!" );
3697 }
3698 }
3699
3700 # Avoid fatals if close() was called
3701 if ( !$this->isOpen() ) {
3702 throw new DBUnexpectedError( $this, "DB connection was already closed." );
3703 }
3704
3705 $this->doRollback( $fname );
3706 $this->mTrxIdleCallbacks = array(); // cancel
3707 $this->mTrxPreCommitCallbacks = array(); // cancel
3708 $this->mTrxAtomicLevels = new SplStack;
3709 if ( $this->mTrxDoneWrites ) {
3710 Profiler::instance()->getTransactionProfiler()->transactionWritingOut(
3711 $this->mServer, $this->mDBname, $this->mTrxShortId );
3712 }
3713 }
3714
3715 /**
3716 * Issues the ROLLBACK command to the database server.
3717 *
3718 * @see DatabaseBase::rollback()
3719 * @param string $fname
3720 */
3721 protected function doRollback( $fname ) {
3722 if ( $this->mTrxLevel ) {
3723 $this->query( 'ROLLBACK', $fname, true );
3724 $this->mTrxLevel = 0;
3725 }
3726 }
3727
3728 /**
3729 * Creates a new table with structure copied from existing table
3730 * Note that unlike most database abstraction functions, this function does not
3731 * automatically append database prefix, because it works at a lower
3732 * abstraction level.
3733 * The table names passed to this function shall not be quoted (this
3734 * function calls addIdentifierQuotes when needed).
3735 *
3736 * @param string $oldName Name of table whose structure should be copied
3737 * @param string $newName Name of table to be created
3738 * @param bool $temporary Whether the new table should be temporary
3739 * @param string $fname Calling function name
3740 * @throws MWException
3741 * @return bool True if operation was successful
3742 */
3743 public function duplicateTableStructure( $oldName, $newName, $temporary = false,
3744 $fname = __METHOD__
3745 ) {
3746 throw new MWException(
3747 'DatabaseBase::duplicateTableStructure is not implemented in descendant class' );
3748 }
3749
3750 /**
3751 * List all tables on the database
3752 *
3753 * @param string $prefix Only show tables with this prefix, e.g. mw_
3754 * @param string $fname Calling function name
3755 * @throws MWException
3756 */
3757 function listTables( $prefix = null, $fname = __METHOD__ ) {
3758 throw new MWException( 'DatabaseBase::listTables is not implemented in descendant class' );
3759 }
3760
3761 /**
3762 * Reset the views process cache set by listViews()
3763 * @since 1.22
3764 */
3765 final public function clearViewsCache() {
3766 $this->allViews = null;
3767 }
3768
3769 /**
3770 * Lists all the VIEWs in the database
3771 *
3772 * For caching purposes the list of all views should be stored in
3773 * $this->allViews. The process cache can be cleared with clearViewsCache()
3774 *
3775 * @param string $prefix Only show VIEWs with this prefix, eg. unit_test_
3776 * @param string $fname Name of calling function
3777 * @throws MWException
3778 * @since 1.22
3779 */
3780 public function listViews( $prefix = null, $fname = __METHOD__ ) {
3781 throw new MWException( 'DatabaseBase::listViews is not implemented in descendant class' );
3782 }
3783
3784 /**
3785 * Differentiates between a TABLE and a VIEW
3786 *
3787 * @param string $name Name of the database-structure to test.
3788 * @throws MWException
3789 * @since 1.22
3790 */
3791 public function isView( $name ) {
3792 throw new MWException( 'DatabaseBase::isView is not implemented in descendant class' );
3793 }
3794
3795 /**
3796 * Convert a timestamp in one of the formats accepted by wfTimestamp()
3797 * to the format used for inserting into timestamp fields in this DBMS.
3798 *
3799 * The result is unquoted, and needs to be passed through addQuotes()
3800 * before it can be included in raw SQL.
3801 *
3802 * @param string|int $ts
3803 *
3804 * @return string
3805 */
3806 public function timestamp( $ts = 0 ) {
3807 return wfTimestamp( TS_MW, $ts );
3808 }
3809
3810 /**
3811 * Convert a timestamp in one of the formats accepted by wfTimestamp()
3812 * to the format used for inserting into timestamp fields in this DBMS. If
3813 * NULL is input, it is passed through, allowing NULL values to be inserted
3814 * into timestamp fields.
3815 *
3816 * The result is unquoted, and needs to be passed through addQuotes()
3817 * before it can be included in raw SQL.
3818 *
3819 * @param string|int $ts
3820 *
3821 * @return string
3822 */
3823 public function timestampOrNull( $ts = null ) {
3824 if ( is_null( $ts ) ) {
3825 return null;
3826 } else {
3827 return $this->timestamp( $ts );
3828 }
3829 }
3830
3831 /**
3832 * Take the result from a query, and wrap it in a ResultWrapper if
3833 * necessary. Boolean values are passed through as is, to indicate success
3834 * of write queries or failure.
3835 *
3836 * Once upon a time, DatabaseBase::query() returned a bare MySQL result
3837 * resource, and it was necessary to call this function to convert it to
3838 * a wrapper. Nowadays, raw database objects are never exposed to external
3839 * callers, so this is unnecessary in external code. For compatibility with
3840 * old code, ResultWrapper objects are passed through unaltered.
3841 *
3842 * @param bool|ResultWrapper|resource $result
3843 * @return bool|ResultWrapper
3844 */
3845 public function resultObject( $result ) {
3846 if ( empty( $result ) ) {
3847 return false;
3848 } elseif ( $result instanceof ResultWrapper ) {
3849 return $result;
3850 } elseif ( $result === true ) {
3851 // Successful write query
3852 return $result;
3853 } else {
3854 return new ResultWrapper( $this, $result );
3855 }
3856 }
3857
3858 /**
3859 * Ping the server and try to reconnect if it there is no connection
3860 *
3861 * @return bool Success or failure
3862 */
3863 public function ping() {
3864 # Stub. Not essential to override.
3865 return true;
3866 }
3867
3868 /**
3869 * Get slave lag. Currently supported only by MySQL.
3870 *
3871 * Note that this function will generate a fatal error on many
3872 * installations. Most callers should use LoadBalancer::safeGetLag()
3873 * instead.
3874 *
3875 * @return int Database replication lag in seconds
3876 */
3877 public function getLag() {
3878 return 0;
3879 }
3880
3881 /**
3882 * Return the maximum number of items allowed in a list, or 0 for unlimited.
3883 *
3884 * @return int
3885 */
3886 function maxListLen() {
3887 return 0;
3888 }
3889
3890 /**
3891 * Some DBMSs have a special format for inserting into blob fields, they
3892 * don't allow simple quoted strings to be inserted. To insert into such
3893 * a field, pass the data through this function before passing it to
3894 * DatabaseBase::insert().
3895 *
3896 * @param string $b
3897 * @return string
3898 */
3899 public function encodeBlob( $b ) {
3900 return $b;
3901 }
3902
3903 /**
3904 * Some DBMSs return a special placeholder object representing blob fields
3905 * in result objects. Pass the object through this function to return the
3906 * original string.
3907 *
3908 * @param string $b
3909 * @return string
3910 */
3911 public function decodeBlob( $b ) {
3912 return $b;
3913 }
3914
3915 /**
3916 * Override database's default behavior. $options include:
3917 * 'connTimeout' : Set the connection timeout value in seconds.
3918 * May be useful for very long batch queries such as
3919 * full-wiki dumps, where a single query reads out over
3920 * hours or days.
3921 *
3922 * @param array $options
3923 * @return void
3924 */
3925 public function setSessionOptions( array $options ) {
3926 }
3927
3928 /**
3929 * Read and execute SQL commands from a file.
3930 *
3931 * Returns true on success, error string or exception on failure (depending
3932 * on object's error ignore settings).
3933 *
3934 * @param string $filename File name to open
3935 * @param bool|callable $lineCallback Optional function called before reading each line
3936 * @param bool|callable $resultCallback Optional function called for each MySQL result
3937 * @param bool|string $fname Calling function name or false if name should be
3938 * generated dynamically using $filename
3939 * @param bool|callable $inputCallback Optional function called for each
3940 * complete line sent
3941 * @throws Exception|MWException
3942 * @return bool|string
3943 */
3944 public function sourceFile(
3945 $filename, $lineCallback = false, $resultCallback = false, $fname = false, $inputCallback = false
3946 ) {
3947 wfSuppressWarnings();
3948 $fp = fopen( $filename, 'r' );
3949 wfRestoreWarnings();
3950
3951 if ( false === $fp ) {
3952 throw new MWException( "Could not open \"{$filename}\".\n" );
3953 }
3954
3955 if ( !$fname ) {
3956 $fname = __METHOD__ . "( $filename )";
3957 }
3958
3959 try {
3960 $error = $this->sourceStream( $fp, $lineCallback, $resultCallback, $fname, $inputCallback );
3961 } catch ( Exception $e ) {
3962 fclose( $fp );
3963 throw $e;
3964 }
3965
3966 fclose( $fp );
3967
3968 return $error;
3969 }
3970
3971 /**
3972 * Get the full path of a patch file. Originally based on archive()
3973 * from updaters.inc. Keep in mind this always returns a patch, as
3974 * it fails back to MySQL if no DB-specific patch can be found
3975 *
3976 * @param string $patch The name of the patch, like patch-something.sql
3977 * @return string Full path to patch file
3978 */
3979 public function patchPath( $patch ) {
3980 global $IP;
3981
3982 $dbType = $this->getType();
3983 if ( file_exists( "$IP/maintenance/$dbType/archives/$patch" ) ) {
3984 return "$IP/maintenance/$dbType/archives/$patch";
3985 } else {
3986 return "$IP/maintenance/archives/$patch";
3987 }
3988 }
3989
3990 /**
3991 * Set variables to be used in sourceFile/sourceStream, in preference to the
3992 * ones in $GLOBALS. If an array is set here, $GLOBALS will not be used at
3993 * all. If it's set to false, $GLOBALS will be used.
3994 *
3995 * @param bool|array $vars Mapping variable name to value.
3996 */
3997 public function setSchemaVars( $vars ) {
3998 $this->mSchemaVars = $vars;
3999 }
4000
4001 /**
4002 * Read and execute commands from an open file handle.
4003 *
4004 * Returns true on success, error string or exception on failure (depending
4005 * on object's error ignore settings).
4006 *
4007 * @param resource $fp File handle
4008 * @param bool|callable $lineCallback Optional function called before reading each query
4009 * @param bool|callable $resultCallback Optional function called for each MySQL result
4010 * @param string $fname Calling function name
4011 * @param bool|callable $inputCallback Optional function called for each complete query sent
4012 * @return bool|string
4013 */
4014 public function sourceStream( $fp, $lineCallback = false, $resultCallback = false,
4015 $fname = __METHOD__, $inputCallback = false
4016 ) {
4017 $cmd = '';
4018
4019 while ( !feof( $fp ) ) {
4020 if ( $lineCallback ) {
4021 call_user_func( $lineCallback );
4022 }
4023
4024 $line = trim( fgets( $fp ) );
4025
4026 if ( $line == '' ) {
4027 continue;
4028 }
4029
4030 if ( '-' == $line[0] && '-' == $line[1] ) {
4031 continue;
4032 }
4033
4034 if ( $cmd != '' ) {
4035 $cmd .= ' ';
4036 }
4037
4038 $done = $this->streamStatementEnd( $cmd, $line );
4039
4040 $cmd .= "$line\n";
4041
4042 if ( $done || feof( $fp ) ) {
4043 $cmd = $this->replaceVars( $cmd );
4044
4045 if ( ( $inputCallback && call_user_func( $inputCallback, $cmd ) ) || !$inputCallback ) {
4046 $res = $this->query( $cmd, $fname );
4047
4048 if ( $resultCallback ) {
4049 call_user_func( $resultCallback, $res, $this );
4050 }
4051
4052 if ( false === $res ) {
4053 $err = $this->lastError();
4054
4055 return "Query \"{$cmd}\" failed with error code \"$err\".\n";
4056 }
4057 }
4058 $cmd = '';
4059 }
4060 }
4061
4062 return true;
4063 }
4064
4065 /**
4066 * Called by sourceStream() to check if we've reached a statement end
4067 *
4068 * @param string $sql SQL assembled so far
4069 * @param string $newLine New line about to be added to $sql
4070 * @return bool Whether $newLine contains end of the statement
4071 */
4072 public function streamStatementEnd( &$sql, &$newLine ) {
4073 if ( $this->delimiter ) {
4074 $prev = $newLine;
4075 $newLine = preg_replace( '/' . preg_quote( $this->delimiter, '/' ) . '$/', '', $newLine );
4076 if ( $newLine != $prev ) {
4077 return true;
4078 }
4079 }
4080
4081 return false;
4082 }
4083
4084 /**
4085 * Database independent variable replacement. Replaces a set of variables
4086 * in an SQL statement with their contents as given by $this->getSchemaVars().
4087 *
4088 * Supports '{$var}' `{$var}` and / *$var* / (without the spaces) style variables.
4089 *
4090 * - '{$var}' should be used for text and is passed through the database's
4091 * addQuotes method.
4092 * - `{$var}` should be used for identifiers (e.g. table and database names).
4093 * It is passed through the database's addIdentifierQuotes method which
4094 * can be overridden if the database uses something other than backticks.
4095 * - / *_* / or / *$wgDBprefix* / passes the name that follows through the
4096 * database's tableName method.
4097 * - / *i* / passes the name that follows through the database's indexName method.
4098 * - In all other cases, / *$var* / is left unencoded. Except for table options,
4099 * its use should be avoided. In 1.24 and older, string encoding was applied.
4100 *
4101 * @param string $ins SQL statement to replace variables in
4102 * @return string The new SQL statement with variables replaced
4103 */
4104 protected function replaceVars( $ins ) {
4105 $that = $this;
4106 $vars = $this->getSchemaVars();
4107 return preg_replace_callback(
4108 '!
4109 /\* (\$wgDBprefix|[_i]) \*/ (\w*) | # 1-2. tableName, indexName
4110 \'\{\$ (\w+) }\' | # 3. addQuotes
4111 `\{\$ (\w+) }` | # 4. addIdentifierQuotes
4112 /\*\$ (\w+) \*/ # 5. leave unencoded
4113 !x',
4114 function ( $m ) use ( $that, $vars ) {
4115 // Note: Because of <https://bugs.php.net/bug.php?id=51881>,
4116 // check for both nonexistent keys *and* the empty string.
4117 if ( isset( $m[1] ) && $m[1] !== '' ) {
4118 if ( $m[1] === 'i' ) {
4119 return $that->indexName( $m[2] );
4120 } else {
4121 return $that->tableName( $m[2] );
4122 }
4123 } elseif ( isset( $m[3] ) && $m[3] !== '' && array_key_exists( $m[3], $vars ) ) {
4124 return $that->addQuotes( $vars[$m[3]] );
4125 } elseif ( isset( $m[4] ) && $m[4] !== '' && array_key_exists( $m[4], $vars ) ) {
4126 return $that->addIdentifierQuotes( $vars[$m[4]] );
4127 } elseif ( isset( $m[5] ) && $m[5] !== '' && array_key_exists( $m[5], $vars ) ) {
4128 return $vars[$m[5]];
4129 } else {
4130 return $m[0];
4131 }
4132 },
4133 $ins
4134 );
4135 }
4136
4137 /**
4138 * Get schema variables. If none have been set via setSchemaVars(), then
4139 * use some defaults from the current object.
4140 *
4141 * @return array
4142 */
4143 protected function getSchemaVars() {
4144 if ( $this->mSchemaVars ) {
4145 return $this->mSchemaVars;
4146 } else {
4147 return $this->getDefaultSchemaVars();
4148 }
4149 }
4150
4151 /**
4152 * Get schema variables to use if none have been set via setSchemaVars().
4153 *
4154 * Override this in derived classes to provide variables for tables.sql
4155 * and SQL patch files.
4156 *
4157 * @return array
4158 */
4159 protected function getDefaultSchemaVars() {
4160 return array();
4161 }
4162
4163 /**
4164 * Check to see if a named lock is available. This is non-blocking.
4165 *
4166 * @param string $lockName Name of lock to poll
4167 * @param string $method Name of method calling us
4168 * @return bool
4169 * @since 1.20
4170 */
4171 public function lockIsFree( $lockName, $method ) {
4172 return true;
4173 }
4174
4175 /**
4176 * Acquire a named lock
4177 *
4178 * Abstracted from Filestore::lock() so child classes can implement for
4179 * their own needs.
4180 *
4181 * @param string $lockName Name of lock to aquire
4182 * @param string $method Name of method calling us
4183 * @param int $timeout
4184 * @return bool
4185 */
4186 public function lock( $lockName, $method, $timeout = 5 ) {
4187 return true;
4188 }
4189
4190 /**
4191 * Release a lock.
4192 *
4193 * @param string $lockName Name of lock to release
4194 * @param string $method Name of method calling us
4195 *
4196 * @return int Returns 1 if the lock was released, 0 if the lock was not established
4197 * by this thread (in which case the lock is not released), and NULL if the named
4198 * lock did not exist
4199 */
4200 public function unlock( $lockName, $method ) {
4201 return true;
4202 }
4203
4204 /**
4205 * Lock specific tables
4206 *
4207 * @param array $read Array of tables to lock for read access
4208 * @param array $write Array of tables to lock for write access
4209 * @param string $method Name of caller
4210 * @param bool $lowPriority Whether to indicate writes to be LOW PRIORITY
4211 * @return bool
4212 */
4213 public function lockTables( $read, $write, $method, $lowPriority = true ) {
4214 return true;
4215 }
4216
4217 /**
4218 * Unlock specific tables
4219 *
4220 * @param string $method The caller
4221 * @return bool
4222 */
4223 public function unlockTables( $method ) {
4224 return true;
4225 }
4226
4227 /**
4228 * Delete a table
4229 * @param string $tableName
4230 * @param string $fName
4231 * @return bool|ResultWrapper
4232 * @since 1.18
4233 */
4234 public function dropTable( $tableName, $fName = __METHOD__ ) {
4235 if ( !$this->tableExists( $tableName, $fName ) ) {
4236 return false;
4237 }
4238 $sql = "DROP TABLE " . $this->tableName( $tableName );
4239 if ( $this->cascadingDeletes() ) {
4240 $sql .= " CASCADE";
4241 }
4242
4243 return $this->query( $sql, $fName );
4244 }
4245
4246 /**
4247 * Get search engine class. All subclasses of this need to implement this
4248 * if they wish to use searching.
4249 *
4250 * @return string
4251 */
4252 public function getSearchEngine() {
4253 return 'SearchEngineDummy';
4254 }
4255
4256 /**
4257 * Find out when 'infinity' is. Most DBMSes support this. This is a special
4258 * keyword for timestamps in PostgreSQL, and works with CHAR(14) as well
4259 * because "i" sorts after all numbers.
4260 *
4261 * @return string
4262 */
4263 public function getInfinity() {
4264 return 'infinity';
4265 }
4266
4267 /**
4268 * Encode an expiry time into the DBMS dependent format
4269 *
4270 * @param string $expiry Timestamp for expiry, or the 'infinity' string
4271 * @return string
4272 */
4273 public function encodeExpiry( $expiry ) {
4274 return ( $expiry == '' || $expiry == 'infinity' || $expiry == $this->getInfinity() )
4275 ? $this->getInfinity()
4276 : $this->timestamp( $expiry );
4277 }
4278
4279 /**
4280 * Decode an expiry time into a DBMS independent format
4281 *
4282 * @param string $expiry DB timestamp field value for expiry
4283 * @param int $format TS_* constant, defaults to TS_MW
4284 * @return string
4285 */
4286 public function decodeExpiry( $expiry, $format = TS_MW ) {
4287 return ( $expiry == '' || $expiry == $this->getInfinity() )
4288 ? 'infinity'
4289 : wfTimestamp( $format, $expiry );
4290 }
4291
4292 /**
4293 * Allow or deny "big selects" for this session only. This is done by setting
4294 * the sql_big_selects session variable.
4295 *
4296 * This is a MySQL-specific feature.
4297 *
4298 * @param bool|string $value True for allow, false for deny, or "default" to
4299 * restore the initial value
4300 */
4301 public function setBigSelects( $value = true ) {
4302 // no-op
4303 }
4304
4305 /**
4306 * @since 1.19
4307 * @return string
4308 */
4309 public function __toString() {
4310 return (string)$this->mConn;
4311 }
4312
4313 /**
4314 * Run a few simple sanity checks
4315 */
4316 public function __destruct() {
4317 if ( $this->mTrxLevel && $this->mTrxDoneWrites ) {
4318 trigger_error( "Uncommitted DB writes (transaction from {$this->mTrxFname})." );
4319 }
4320 if ( count( $this->mTrxIdleCallbacks ) || count( $this->mTrxPreCommitCallbacks ) ) {
4321 $callers = array();
4322 foreach ( $this->mTrxIdleCallbacks as $callbackInfo ) {
4323 $callers[] = $callbackInfo[1];
4324 }
4325 $callers = implode( ', ', $callers );
4326 trigger_error( "DB transaction callbacks still pending (from $callers)." );
4327 }
4328 }
4329 }