3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
16 * http://www.gnu.org/copyleft/gpl.html
20 namespace Wikimedia\Rdbms
;
22 use InvalidArgumentException
;
23 use Wikimedia\ScopedCallback
;
25 use UnexpectedValueException
;
29 * @defgroup Database Database
30 * This group deals with database interface functions
31 * and query specifics/optimisations.
34 * Basic database interface for live and lazy-loaded relation database handles
36 * @note: IDatabase and DBConnRef should be updated to reflect any changes
40 /** @var int Callback triggered immediately due to no active transaction */
41 const TRIGGER_IDLE
= 1;
42 /** @var int Callback triggered by COMMIT */
43 const TRIGGER_COMMIT
= 2;
44 /** @var int Callback triggered by ROLLBACK */
45 const TRIGGER_ROLLBACK
= 3;
47 /** @var string Transaction is requested by regular caller outside of the DB layer */
48 const TRANSACTION_EXPLICIT
= '';
49 /** @var string Transaction is requested internally via DBO_TRX/startAtomic() */
50 const TRANSACTION_INTERNAL
= 'implicit';
52 /** @var string Atomic section is not cancelable */
53 const ATOMIC_NOT_CANCELABLE
= '';
54 /** @var string Atomic section is cancelable */
55 const ATOMIC_CANCELABLE
= 'cancelable';
57 /** @var string Transaction operation comes from service managing all DBs */
58 const FLUSHING_ALL_PEERS
= 'flush';
59 /** @var string Transaction operation comes from the database class internally */
60 const FLUSHING_INTERNAL
= 'flush';
62 /** @var string Do not remember the prior flags */
63 const REMEMBER_NOTHING
= '';
64 /** @var string Remember the prior flags */
65 const REMEMBER_PRIOR
= 'remember';
66 /** @var string Restore to the prior flag state */
67 const RESTORE_PRIOR
= 'prior';
68 /** @var string Restore to the initial flag state */
69 const RESTORE_INITIAL
= 'initial';
71 /** @var string Estimate total time (RTT, scanning, waiting on locks, applying) */
72 const ESTIMATE_TOTAL
= 'total';
73 /** @var string Estimate time to apply (scanning, applying) */
74 const ESTIMATE_DB_APPLY
= 'apply';
76 /** @var int Combine list with comma delimeters */
78 /** @var int Combine list with AND clauses */
80 /** @var int Convert map into a SET clause */
82 /** @var int Treat as field name and do not apply value escaping */
84 /** @var int Combine list with OR clauses */
87 /** @var int Enable debug logging */
89 /** @var int Disable query buffering (only one result set can be iterated at a time) */
90 const DBO_NOBUFFER
= 2;
91 /** @var int Ignore query errors (internal use only!) */
93 /** @var int Autoatically start transaction on first query (work with ILoadBalancer rounds) */
95 /** @var int Use DBO_TRX in non-CLI mode */
96 const DBO_DEFAULT
= 16;
97 /** @var int Use DB persistent connections if possible */
98 const DBO_PERSISTENT
= 32;
99 /** @var int DBA session mode; mostly for Oracle */
100 const DBO_SYSDBA
= 64;
101 /** @var int Schema file mode; mostly for Oracle */
102 const DBO_DDLMODE
= 128;
103 /** @var int Enable SSL/TLS in connection protocol */
105 /** @var int Enable compression in connection protocol */
106 const DBO_COMPRESS
= 512;
109 * A string describing the current software version, and possibly
110 * other details in a user-friendly way. Will be listed on Special:Version, etc.
111 * Use getServerVersion() to get machine-friendly information.
113 * @return string Version information from the database server
115 public function getServerInfo();
118 * Turns buffering of SQL result sets on (true) or off (false). Default is "on".
120 * Unbuffered queries are very troublesome in MySQL:
122 * - If another query is executed while the first query is being read
123 * out, the first query is killed. This means you can't call normal
124 * Database functions while you are reading an unbuffered query result
125 * from a normal Database connection.
127 * - Unbuffered queries cause the MySQL server to use large amounts of
128 * memory and to hold broad locks which block other queries.
130 * If you want to limit client-side memory, it's almost always better to
131 * split up queries into batches using a LIMIT clause than to switch off
134 * @param null|bool $buffer
135 * @return null|bool The previous value of the flag
137 public function bufferResults( $buffer = null );
140 * Gets the current transaction level.
142 * Historically, transactions were allowed to be "nested". This is no
143 * longer supported, so this function really only returns a boolean.
145 * @return int The previous value
147 public function trxLevel();
150 * Get the UNIX timestamp of the time that the transaction was established
152 * This can be used to reason about the staleness of SELECT data
153 * in REPEATABLE-READ transaction isolation level.
155 * @return float|null Returns null if there is not active transaction
158 public function trxTimestamp();
161 * @return bool Whether an explicit transaction or atomic sections are still open
164 public function explicitTrxActive();
167 * Get/set the table prefix.
168 * @param string $prefix The table prefix to set, or omitted to leave it unchanged.
169 * @return string The previous table prefix.
171 public function tablePrefix( $prefix = null );
174 * Get/set the db schema.
175 * @param string $schema The database schema to set, or omitted to leave it unchanged.
176 * @return string The previous db schema.
178 public function dbSchema( $schema = null );
181 * Get properties passed down from the server info array of the load
184 * @param string $name The entry of the info array to get, or null to get the
187 * @return array|mixed|null
189 public function getLBInfo( $name = null );
192 * Set the LB info array, or a member of it. If called with one parameter,
193 * the LB info array is set to that parameter. If it is called with two
194 * parameters, the member with the given name is set to the given value.
196 * @param string $name
197 * @param array $value
199 public function setLBInfo( $name, $value = null );
202 * Set a lazy-connecting DB handle to the master DB (for replication status purposes)
204 * @param IDatabase $conn
207 public function setLazyMasterHandle( IDatabase
$conn );
210 * Returns true if this database does an implicit sort when doing GROUP BY
213 * @deprecated Since 1.30; only use grouped or aggregated fields in the SELECT
215 public function implicitGroupby();
218 * Returns true if this database does an implicit order by when the column has an index
219 * For example: SELECT page_title FROM page LIMIT 1
223 public function implicitOrderby();
226 * Return the last query that went through IDatabase::query()
229 public function lastQuery();
232 * Returns true if the connection may have been used for write queries.
233 * Should return true if unsure.
236 * @deprecated Since 1.31; use lastDoneWrites()
238 public function doneWrites();
241 * Returns the last time the connection may have been used for write queries.
242 * Should return a timestamp if unsure.
244 * @return int|float UNIX timestamp or false
247 public function lastDoneWrites();
250 * @return bool Whether there is a transaction open with possible write queries
253 public function writesPending();
256 * Returns true if there is a transaction open with possible write
257 * queries or transaction pre-commit/idle callbacks waiting on it to finish.
258 * This does *not* count recurring callbacks, e.g. from setTransactionListener().
262 public function writesOrCallbacksPending();
265 * Get the time spend running write queries for this transaction
267 * High times could be due to scanning, updates, locking, and such
269 * @param string $type IDatabase::ESTIMATE_* constant [default: ESTIMATE_ALL]
270 * @return float|bool Returns false if not transaction is active
273 public function pendingWriteQueryDuration( $type = self
::ESTIMATE_TOTAL
);
276 * Get the list of method names that did write queries for this transaction
281 public function pendingWriteCallers();
284 * Get the number of affected rows from pending write queries
289 public function pendingWriteRowsAffected();
292 * Is a connection to the database open?
295 public function isOpen();
298 * Set a flag for this connection
300 * @param int $flag DBO_* constants from Defines.php:
301 * - DBO_DEBUG: output some debug info (same as debug())
302 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
303 * - DBO_TRX: automatically start transactions
304 * - DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode
305 * and removes it in command line mode
306 * - DBO_PERSISTENT: use persistant database connection
307 * @param string $remember IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]
309 public function setFlag( $flag, $remember = self
::REMEMBER_NOTHING
);
312 * Clear a flag for this connection
314 * @param int $flag DBO_* constants from Defines.php:
315 * - DBO_DEBUG: output some debug info (same as debug())
316 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
317 * - DBO_TRX: automatically start transactions
318 * - DBO_DEFAULT: automatically sets DBO_TRX if not in command line mode
319 * and removes it in command line mode
320 * - DBO_PERSISTENT: use persistant database connection
321 * @param string $remember IDatabase::REMEMBER_* constant [default: REMEMBER_NOTHING]
323 public function clearFlag( $flag, $remember = self
::REMEMBER_NOTHING
);
326 * Restore the flags to their prior state before the last setFlag/clearFlag call
328 * @param string $state IDatabase::RESTORE_* constant. [default: RESTORE_PRIOR]
331 public function restoreFlags( $state = self
::RESTORE_PRIOR
);
334 * Returns a boolean whether the flag $flag is set for this connection
336 * @param int $flag DBO_* constants from Defines.php:
337 * - DBO_DEBUG: output some debug info (same as debug())
338 * - DBO_NOBUFFER: don't buffer results (inverse of bufferResults())
339 * - DBO_TRX: automatically start transactions
340 * - DBO_PERSISTENT: use persistant database connection
343 public function getFlag( $flag );
348 public function getDomainID();
351 * Alias for getDomainID()
356 public function getWikiID();
359 * Get the type of the DBMS, as it appears in $wgDBtype.
363 public function getType();
366 * Open a new connection to the database (closing any existing one)
368 * @param string $server Database server host
369 * @param string $user Database user name
370 * @param string $password Database user password
371 * @param string $dbName Database name
373 * @throws DBConnectionError
375 public function open( $server, $user, $password, $dbName );
378 * Fetch the next row from the given result object, in object form.
379 * Fields can be retrieved with $row->fieldname, with fields acting like
381 * If no more rows are available, false is returned.
383 * @param IResultWrapper|stdClass $res Object as returned from IDatabase::query(), etc.
384 * @return stdClass|bool
385 * @throws DBUnexpectedError Thrown if the database returns an error
387 public function fetchObject( $res );
390 * Fetch the next row from the given result object, in associative array
391 * form. Fields are retrieved with $row['fieldname'].
392 * If no more rows are available, false is returned.
394 * @param IResultWrapper $res Result object as returned from IDatabase::query(), etc.
396 * @throws DBUnexpectedError Thrown if the database returns an error
398 public function fetchRow( $res );
401 * Get the number of rows in a result object
403 * @param mixed $res A SQL result
406 public function numRows( $res );
409 * Get the number of fields in a result object
410 * @see https://secure.php.net/mysql_num_fields
412 * @param mixed $res A SQL result
415 public function numFields( $res );
418 * Get a field name in a result object
419 * @see https://secure.php.net/mysql_field_name
421 * @param mixed $res A SQL result
425 public function fieldName( $res, $n );
428 * Get the inserted value of an auto-increment row
430 * This should only be called after an insert that used an auto-incremented
431 * value. If no such insert was previously done in the current database
432 * session, the return value is undefined.
436 public function insertId();
439 * Change the position of the cursor in a result object
440 * @see https://secure.php.net/mysql_data_seek
442 * @param mixed $res A SQL result
445 public function dataSeek( $res, $row );
448 * Get the last error number
449 * @see https://secure.php.net/mysql_errno
453 public function lastErrno();
456 * Get a description of the last error
457 * @see https://secure.php.net/mysql_error
461 public function lastError();
464 * Get the number of rows affected by the last write query
465 * @see https://secure.php.net/mysql_affected_rows
469 public function affectedRows();
472 * Returns a wikitext link to the DB's website, e.g.,
473 * return "[https://www.mysql.com/ MySQL]";
474 * Should at least contain plain text, if for some reason
475 * your database has no website.
477 * @return string Wikitext of a link to the server software's web site
479 public function getSoftwareLink();
482 * A string describing the current software version, like from
483 * mysql_get_server_info().
485 * @return string Version information from the database server.
487 public function getServerVersion();
490 * Close the database connection
492 * This should only be called after any transactions have been resolved,
493 * aside from read-only transactions (assuming no callbacks are registered).
494 * If a transaction is still open anyway, it will be committed if possible.
497 * @return bool Operation success. true if already closed.
499 public function close();
502 * Run an SQL query and return the result. Normally throws a DBQueryError
503 * on failure. If errors are ignored, returns false instead.
505 * If a connection loss is detected, then an attempt to reconnect will be made.
506 * For queries that involve no larger transactions or locks, they will be re-issued
507 * for convenience, provided the connection was re-established.
509 * In new code, the query wrappers select(), insert(), update(), delete(),
510 * etc. should be used where possible, since they give much better DBMS
511 * independence and automatically quote or validate user input in a variety
512 * of contexts. This function is generally only useful for queries which are
513 * explicitly DBMS-dependent and are unsupported by the query wrappers, such
516 * However, the query wrappers themselves should call this function.
518 * @param string $sql SQL query
519 * @param string $fname Name of the calling function, for profiling/SHOW PROCESSLIST
520 * comment (you can use __METHOD__ or add some extra info)
521 * @param bool $tempIgnore Whether to avoid throwing an exception on errors...
522 * maybe best to catch the exception instead?
523 * @return bool|IResultWrapper True for a successful write query, IResultWrapper object
524 * for a successful read query, or false on failure if $tempIgnore set
527 public function query( $sql, $fname = __METHOD__
, $tempIgnore = false );
530 * Free a result object returned by query() or select(). It's usually not
531 * necessary to call this, just use unset() or let the variable holding
532 * the result object go out of scope.
534 * @param mixed $res A SQL result
536 public function freeResult( $res );
539 * A SELECT wrapper which returns a single field from a single result row.
541 * Usually throws a DBQueryError on failure. If errors are explicitly
542 * ignored, returns false on failure.
544 * If no result rows are returned from the query, false is returned.
546 * @param string|array $table Table name. See IDatabase::select() for details.
547 * @param string $var The field name to select. This must be a valid SQL
548 * fragment: do not use unvalidated user input.
549 * @param string|array $cond The condition array. See IDatabase::select() for details.
550 * @param string $fname The function name of the caller.
551 * @param string|array $options The query options. See IDatabase::select() for details.
552 * @param string|array $join_conds The query join conditions. See IDatabase::select() for details.
554 * @return mixed The value from the field
557 public function selectField(
558 $table, $var, $cond = '', $fname = __METHOD__
, $options = [], $join_conds = []
562 * A SELECT wrapper which returns a list of single field values from result rows.
564 * Usually throws a DBQueryError on failure. If errors are explicitly
565 * ignored, returns false on failure.
567 * If no result rows are returned from the query, false is returned.
569 * @param string|array $table Table name. See IDatabase::select() for details.
570 * @param string $var The field name to select. This must be a valid SQL
571 * fragment: do not use unvalidated user input.
572 * @param string|array $cond The condition array. See IDatabase::select() for details.
573 * @param string $fname The function name of the caller.
574 * @param string|array $options The query options. See IDatabase::select() for details.
575 * @param string|array $join_conds The query join conditions. See IDatabase::select() for details.
577 * @return array The values from the field
581 public function selectFieldValues(
582 $table, $var, $cond = '', $fname = __METHOD__
, $options = [], $join_conds = []
586 * Execute a SELECT query constructed using the various parameters provided.
587 * See below for full details of the parameters.
589 * @param string|array $table Table name
590 * @param string|array $vars Field names
591 * @param string|array $conds Conditions
592 * @param string $fname Caller function name
593 * @param array $options Query options
594 * @param array $join_conds Join conditions
597 * @param string|array $table
599 * May be either an array of table names, or a single string holding a table
600 * name. If an array is given, table aliases can be specified, for example:
604 * This includes the user table in the query, with the alias "a" available
605 * for use in field names (e.g. a.user_name).
607 * A derived table, defined by the result of selectSQLText(), requires an alias
608 * key and a Subquery instance value which wraps the SQL query, for example:
610 * [ 'c' => new Subquery( 'SELECT ...' ) ]
612 * Joins using parentheses for grouping (since MediaWiki 1.31) may be
613 * constructed using nested arrays. For example,
615 * [ 'tableA', 'nestedB' => [ 'tableB', 'b2' => 'tableB2' ] ]
617 * along with `$join_conds` like
619 * [ 'b2' => [ 'JOIN', 'b_id = b2_id' ], 'nestedB' => [ 'LEFT JOIN', 'b_a = a_id' ] ]
621 * will produce SQL something like
623 * FROM tableA LEFT JOIN (tableB JOIN tableB2 AS b2 ON (b_id = b2_id)) ON (b_a = a_id)
625 * All of the table names given here are automatically run through
626 * Database::tableName(), which causes the table prefix (if any) to be
627 * added, and various other table name mappings to be performed.
629 * Do not use untrusted user input as a table name. Alias names should
630 * not have characters outside of the Basic multilingual plane.
632 * @param string|array $vars
634 * May be either a field name or an array of field names. The field names
635 * can be complete fragments of SQL, for direct inclusion into the SELECT
636 * query. If an array is given, field aliases can be specified, for example:
638 * [ 'maxrev' => 'MAX(rev_id)' ]
640 * This includes an expression with the alias "maxrev" in the query.
642 * If an expression is given, care must be taken to ensure that it is
645 * Untrusted user input must not be passed to this parameter.
647 * @param string|array $conds
649 * May be either a string containing a single condition, or an array of
650 * conditions. If an array is given, the conditions constructed from each
651 * element are combined with AND.
653 * Array elements may take one of two forms:
655 * - Elements with a numeric key are interpreted as raw SQL fragments.
656 * - Elements with a string key are interpreted as equality conditions,
657 * where the key is the field name.
658 * - If the value of such an array element is a scalar (such as a
659 * string), it will be treated as data and thus quoted appropriately.
660 * If it is null, an IS NULL clause will be added.
661 * - If the value is an array, an IN (...) clause will be constructed
662 * from its non-null elements, and an IS NULL clause will be added
663 * if null is present, such that the field may match any of the
664 * elements in the array. The non-null elements will be quoted.
666 * Note that expressions are often DBMS-dependent in their syntax.
667 * DBMS-independent wrappers are provided for constructing several types of
668 * expression commonly used in condition queries. See:
669 * - IDatabase::buildLike()
670 * - IDatabase::conditional()
672 * Untrusted user input is safe in the values of string keys, however untrusted
673 * input must not be used in the array key names or in the values of numeric keys.
674 * Escaping of untrusted input used in values of numeric keys should be done via
675 * IDatabase::addQuotes()
677 * @param string|array $options
679 * Optional: Array of query options. Boolean options are specified by
680 * including them in the array as a string value with a numeric key, for
685 * The supported options are:
687 * - OFFSET: Skip this many rows at the start of the result set. OFFSET
688 * with LIMIT can theoretically be used for paging through a result set,
689 * but this is discouraged for performance reasons.
691 * - LIMIT: Integer: return at most this many rows. The rows are sorted
692 * and then the first rows are taken until the limit is reached. LIMIT
693 * is applied to a result set after OFFSET.
695 * - FOR UPDATE: Boolean: lock the returned rows so that they can't be
696 * changed until the next COMMIT.
698 * - DISTINCT: Boolean: return only unique result rows.
700 * - GROUP BY: May be either an SQL fragment string naming a field or
701 * expression to group by, or an array of such SQL fragments.
703 * - HAVING: May be either an string containing a HAVING clause or an array of
704 * conditions building the HAVING clause. If an array is given, the conditions
705 * constructed from each element are combined with AND.
707 * - ORDER BY: May be either an SQL fragment giving a field name or
708 * expression to order by, or an array of such SQL fragments.
710 * - USE INDEX: This may be either a string giving the index name to use
711 * for the query, or an array. If it is an associative array, each key
712 * gives the table name (or alias), each value gives the index name to
713 * use for that table. All strings are SQL fragments and so should be
714 * validated by the caller.
716 * - EXPLAIN: In MySQL, this causes an EXPLAIN SELECT query to be run,
719 * And also the following boolean MySQL extensions, see the MySQL manual
722 * - LOCK IN SHARE MODE
726 * - SQL_BUFFER_RESULT
728 * - SQL_CALC_FOUND_ROWS
733 * @param string|array $join_conds
735 * Optional associative array of table-specific join conditions. In the
736 * most common case, this is unnecessary, since the join condition can be
737 * in $conds. However, it is useful for doing a LEFT JOIN.
739 * The key of the array contains the table name or alias. The value is an
740 * array with two elements, numbered 0 and 1. The first gives the type of
741 * join, the second is the same as the $conds parameter. Thus it can be
742 * an SQL fragment, or an array where the string keys are equality and the
743 * numeric keys are SQL fragments all AND'd together. For example:
745 * [ 'page' => [ 'LEFT JOIN', 'page_latest=rev_id' ] ]
747 * @return IResultWrapper Resulting rows
750 public function select(
751 $table, $vars, $conds = '', $fname = __METHOD__
,
752 $options = [], $join_conds = []
756 * The equivalent of IDatabase::select() except that the constructed SQL
757 * is returned, instead of being immediately executed. This can be useful for
758 * doing UNION queries, where the SQL text of each query is needed. In general,
759 * however, callers outside of Database classes should just use select().
761 * @see IDatabase::select()
763 * @param string|array $table Table name
764 * @param string|array $vars Field names
765 * @param string|array $conds Conditions
766 * @param string $fname Caller function name
767 * @param string|array $options Query options
768 * @param string|array $join_conds Join conditions
769 * @return string SQL query string
771 public function selectSQLText(
772 $table, $vars, $conds = '', $fname = __METHOD__
,
773 $options = [], $join_conds = []
777 * Single row SELECT wrapper. Equivalent to IDatabase::select(), except
778 * that a single row object is returned. If the query returns no rows,
781 * @param string|array $table Table name
782 * @param string|array $vars Field names
783 * @param array $conds Conditions
784 * @param string $fname Caller function name
785 * @param string|array $options Query options
786 * @param array|string $join_conds Join conditions
788 * @return stdClass|bool
791 public function selectRow( $table, $vars, $conds, $fname = __METHOD__
,
792 $options = [], $join_conds = []
796 * Estimate the number of rows in dataset
798 * MySQL allows you to estimate the number of rows that would be returned
799 * by a SELECT query, using EXPLAIN SELECT. The estimate is provided using
800 * index cardinality statistics, and is notoriously inaccurate, especially
801 * when large numbers of rows have recently been added or deleted.
803 * For DBMSs that don't support fast result size estimation, this function
804 * will actually perform the SELECT COUNT(*).
806 * Takes the same arguments as IDatabase::select().
808 * @param string $table Table name
809 * @param string $var Column for which NULL values are not counted [default "*"]
810 * @param array|string $conds Filters on the table
811 * @param string $fname Function name for profiling
812 * @param array $options Options for select
813 * @param array|string $join_conds Join conditions
814 * @return int Row count
817 public function estimateRowCount(
818 $table, $var = '*', $conds = '', $fname = __METHOD__
, $options = [], $join_conds = []
822 * Get the number of rows in dataset
824 * This is useful when trying to do COUNT(*) but with a LIMIT for performance.
826 * Takes the same arguments as IDatabase::select().
828 * @since 1.27 Added $join_conds parameter
830 * @param array|string $tables Table names
831 * @param string $var Column for which NULL values are not counted [default "*"]
832 * @param array|string $conds Filters on the table
833 * @param string $fname Function name for profiling
834 * @param array $options Options for select
835 * @param array $join_conds Join conditions (since 1.27)
836 * @return int Row count
839 public function selectRowCount(
840 $tables, $var = '*', $conds = '', $fname = __METHOD__
, $options = [], $join_conds = []
844 * Determines whether a field exists in a table
846 * @param string $table Table name
847 * @param string $field Filed to check on that table
848 * @param string $fname Calling function name (optional)
849 * @return bool Whether $table has filed $field
852 public function fieldExists( $table, $field, $fname = __METHOD__
);
855 * Determines whether an index exists
856 * Usually throws a DBQueryError on failure
857 * If errors are explicitly ignored, returns NULL on failure
859 * @param string $table
860 * @param string $index
861 * @param string $fname
865 public function indexExists( $table, $index, $fname = __METHOD__
);
868 * Query whether a given table exists
870 * @param string $table
871 * @param string $fname
875 public function tableExists( $table, $fname = __METHOD__
);
878 * INSERT wrapper, inserts an array into a table.
882 * - A single associative array. The array keys are the field names, and
883 * the values are the values to insert. The values are treated as data
884 * and will be quoted appropriately. If NULL is inserted, this will be
885 * converted to a database NULL.
886 * - An array with numeric keys, holding a list of associative arrays.
887 * This causes a multi-row INSERT on DBMSs that support it. The keys in
888 * each subarray must be identical to each other, and in the same order.
890 * Usually throws a DBQueryError on failure. If errors are explicitly ignored,
893 * $options is an array of options, with boolean options encoded as values
894 * with numeric keys, in the same style as $options in
895 * IDatabase::select(). Supported options are:
897 * - IGNORE: Boolean: if present, duplicate key errors are ignored, and
898 * any rows which cause duplicate key errors are not inserted. It's
899 * possible to determine how many rows were successfully inserted using
900 * IDatabase::affectedRows().
902 * @param string $table Table name. This will be passed through
903 * Database::tableName().
904 * @param array $a Array of rows to insert
905 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
906 * @param array $options Array of options
911 public function insert( $table, $a, $fname = __METHOD__
, $options = [] );
914 * UPDATE wrapper. Takes a condition array and a SET array.
916 * @param string $table Name of the table to UPDATE. This will be passed through
917 * Database::tableName().
918 * @param array $values An array of values to SET. For each array element,
919 * the key gives the field name, and the value gives the data to set
920 * that field to. The data will be quoted by IDatabase::addQuotes().
921 * Values with integer keys form unquoted SET statements, which can be used for
922 * things like "field = field + 1" or similar computed values.
923 * @param array $conds An array of conditions (WHERE). See
924 * IDatabase::select() for the details of the format of condition
925 * arrays. Use '*' to update all rows.
926 * @param string $fname The function name of the caller (from __METHOD__),
927 * for logging and profiling.
928 * @param array $options An array of UPDATE options, can be:
929 * - IGNORE: Ignore unique key conflicts
930 * - LOW_PRIORITY: MySQL-specific, see MySQL manual.
934 public function update( $table, $values, $conds, $fname = __METHOD__
, $options = [] );
937 * Makes an encoded list of strings from an array
939 * These can be used to make conjunctions or disjunctions on SQL condition strings
940 * derived from an array (see IDatabase::select() $conds documentation).
944 * $sql = $db->makeList( [
946 * $db->makeList( [ 'rev_minor' => 1, 'rev_len' < 500 ], $db::LIST_OR ] )
947 * ], $db::LIST_AND );
949 * This would set $sql to "rev_page = '$id' AND (rev_minor = '1' OR rev_len < '500')"
951 * @param array $a Containing the data
952 * @param int $mode IDatabase class constant:
953 * - IDatabase::LIST_COMMA: Comma separated, no field names
954 * - IDatabase::LIST_AND: ANDed WHERE clause (without the WHERE).
955 * - IDatabase::LIST_OR: ORed WHERE clause (without the WHERE)
956 * - IDatabase::LIST_SET: Comma separated with field names, like a SET clause
957 * - IDatabase::LIST_NAMES: Comma separated field names
961 public function makeList( $a, $mode = self
::LIST_COMMA
);
964 * Build a partial where clause from a 2-d array such as used for LinkBatch.
965 * The keys on each level may be either integers or strings.
967 * @param array $data Organized as 2-d
968 * [ baseKeyVal => [ subKeyVal => [ignored], ... ], ... ]
969 * @param string $baseKey Field name to match the base-level keys to (eg 'pl_namespace')
970 * @param string $subKey Field name to match the sub-level keys to (eg 'pl_title')
971 * @return string|bool SQL fragment, or false if no items in array
973 public function makeWhereFrom2d( $data, $baseKey, $subKey );
976 * Return aggregated value alias
978 * @param array $valuedata
979 * @param string $valuename
983 public function aggregateValue( $valuedata, $valuename = 'value' );
986 * @param string $field
989 public function bitNot( $field );
992 * @param string $fieldLeft
993 * @param string $fieldRight
996 public function bitAnd( $fieldLeft, $fieldRight );
999 * @param string $fieldLeft
1000 * @param string $fieldRight
1003 public function bitOr( $fieldLeft, $fieldRight );
1006 * Build a concatenation list to feed into a SQL query
1007 * @param array $stringList List of raw SQL expressions; caller is
1008 * responsible for any quoting
1011 public function buildConcat( $stringList );
1014 * Build a GROUP_CONCAT or equivalent statement for a query.
1016 * This is useful for combining a field for several rows into a single string.
1017 * NULL values will not appear in the output, duplicated values will appear,
1018 * and the resulting delimiter-separated values have no defined sort order.
1019 * Code using the results may need to use the PHP unique() or sort() methods.
1021 * @param string $delim Glue to bind the results together
1022 * @param string|array $table Table name
1023 * @param string $field Field name
1024 * @param string|array $conds Conditions
1025 * @param string|array $join_conds Join conditions
1026 * @return string SQL text
1029 public function buildGroupConcatField(
1030 $delim, $table, $field, $conds = '', $join_conds = []
1034 * Build a SUBSTRING function.
1036 * Behavior for non-ASCII values is undefined.
1038 * @param string $input Field name
1039 * @param int $startPosition Positive integer
1040 * @param int|null $length Non-negative integer length or null for no limit
1041 * @throws InvalidArgumentException
1042 * @return string SQL text
1045 public function buildSubString( $input, $startPosition, $length = null );
1048 * @param string $field Field or column to cast
1052 public function buildStringCast( $field );
1055 * @param string $field Field or column to cast
1059 public function buildIntegerCast( $field );
1062 * Equivalent to IDatabase::selectSQLText() except wraps the result in Subqyery
1064 * @see IDatabase::selectSQLText()
1066 * @param string|array $table Table name
1067 * @param string|array $vars Field names
1068 * @param string|array $conds Conditions
1069 * @param string $fname Caller function name
1070 * @param string|array $options Query options
1071 * @param string|array $join_conds Join conditions
1075 public function buildSelectSubquery(
1076 $table, $vars, $conds = '', $fname = __METHOD__
,
1077 $options = [], $join_conds = []
1081 * Returns true if DBs are assumed to be on potentially different servers
1083 * In systems like mysql/mariadb, different databases can easily be referenced on a single
1084 * connection merely by name, even in a single query via JOIN. On the other hand, Postgres
1085 * treats databases as fully separate, only allowing mechanisms like postgres_fdw to
1086 * effectively "mount" foreign DBs. This is true even among DBs on the same server.
1091 public function databasesAreIndependent();
1094 * Change the current database
1097 * @return bool Success or failure
1098 * @throws DBConnectionError If databasesAreIndependent() is true and an error occurs
1100 public function selectDB( $db );
1103 * Get the current DB name
1106 public function getDBname();
1109 * Get the server hostname or IP address
1112 public function getServer();
1115 * Adds quotes and backslashes.
1117 * @param string|int|null|bool|Blob $s
1118 * @return string|int
1120 public function addQuotes( $s );
1123 * LIKE statement wrapper, receives a variable-length argument list with
1124 * parts of pattern to match containing either string literals that will be
1125 * escaped or tokens returned by anyChar() or anyString(). Alternatively,
1126 * the function could be provided with an array of aforementioned
1129 * Example: $dbr->buildLike( 'My_page_title/', $dbr->anyString() ) returns
1130 * a LIKE clause that searches for subpages of 'My page title'.
1132 * $pattern = [ 'My_page_title/', $dbr->anyString() ];
1133 * $query .= $dbr->buildLike( $pattern );
1136 * @return string Fully built LIKE statement
1138 public function buildLike();
1141 * Returns a token for buildLike() that denotes a '_' to be used in a LIKE query
1145 public function anyChar();
1148 * Returns a token for buildLike() that denotes a '%' to be used in a LIKE query
1152 public function anyString();
1155 * Deprecated method, calls should be removed.
1157 * This was formerly used for PostgreSQL and Oracle to handle
1158 * self::insertId() auto-incrementing fields. It is no longer necessary
1159 * since DatabasePostgres::insertId() has been reimplemented using
1160 * `lastval()` and Oracle has been reimplemented using triggers.
1162 * Implementations should return null if inserting `NULL` into an
1163 * auto-incrementing field works, otherwise it should return an instance of
1164 * NextSequenceValue and filter it on calls to relevant methods.
1166 * @deprecated since 1.30, no longer needed
1167 * @param string $seqName
1168 * @return null|NextSequenceValue
1170 public function nextSequenceValue( $seqName );
1173 * REPLACE query wrapper.
1175 * REPLACE is a very handy MySQL extension, which functions like an INSERT
1176 * except that when there is a duplicate key error, the old row is deleted
1177 * and the new row is inserted in its place.
1179 * We simulate this with standard SQL with a DELETE followed by INSERT. To
1180 * perform the delete, we need to know what the unique indexes are so that
1181 * we know how to find the conflicting rows.
1183 * It may be more efficient to leave off unique indexes which are unlikely
1184 * to collide. However if you do this, you run the risk of encountering
1185 * errors which wouldn't have occurred in MySQL.
1187 * @param string $table The table to replace the row(s) in.
1188 * @param array $uniqueIndexes Is an array of indexes. Each element may be either
1189 * a field name or an array of field names
1190 * @param array $rows Can be either a single row to insert, or multiple rows,
1191 * in the same format as for IDatabase::insert()
1192 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
1195 public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__
);
1198 * INSERT ON DUPLICATE KEY UPDATE wrapper, upserts an array into a table.
1200 * This updates any conflicting rows (according to the unique indexes) using
1201 * the provided SET clause and inserts any remaining (non-conflicted) rows.
1203 * $rows may be either:
1204 * - A single associative array. The array keys are the field names, and
1205 * the values are the values to insert. The values are treated as data
1206 * and will be quoted appropriately. If NULL is inserted, this will be
1207 * converted to a database NULL.
1208 * - An array with numeric keys, holding a list of associative arrays.
1209 * This causes a multi-row INSERT on DBMSs that support it. The keys in
1210 * each subarray must be identical to each other, and in the same order.
1212 * It may be more efficient to leave off unique indexes which are unlikely
1213 * to collide. However if you do this, you run the risk of encountering
1214 * errors which wouldn't have occurred in MySQL.
1216 * Usually throws a DBQueryError on failure. If errors are explicitly ignored,
1221 * @param string $table Table name. This will be passed through Database::tableName().
1222 * @param array $rows A single row or list of rows to insert
1223 * @param array $uniqueIndexes List of single field names or field name tuples
1224 * @param array $set An array of values to SET. For each array element, the
1225 * key gives the field name, and the value gives the data to set that
1226 * field to. The data will be quoted by IDatabase::addQuotes().
1227 * Values with integer keys form unquoted SET statements, which can be used for
1228 * things like "field = field + 1" or similar computed values.
1229 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
1233 public function upsert(
1234 $table, array $rows, array $uniqueIndexes, array $set, $fname = __METHOD__
1238 * DELETE where the condition is a join.
1240 * MySQL overrides this to use a multi-table DELETE syntax, in other databases
1241 * we use sub-selects
1243 * For safety, an empty $conds will not delete everything. If you want to
1244 * delete all rows where the join condition matches, set $conds='*'.
1246 * DO NOT put the join condition in $conds.
1248 * @param string $delTable The table to delete from.
1249 * @param string $joinTable The other table.
1250 * @param string $delVar The variable to join on, in the first table.
1251 * @param string $joinVar The variable to join on, in the second table.
1252 * @param array $conds Condition array of field names mapped to variables,
1253 * ANDed together in the WHERE clause
1254 * @param string $fname Calling function name (use __METHOD__) for logs/profiling
1257 public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
1262 * DELETE query wrapper.
1264 * @param string $table Table name
1265 * @param string|array $conds Array of conditions. See $conds in IDatabase::select()
1266 * for the format. Use $conds == "*" to delete all rows
1267 * @param string $fname Name of the calling function
1268 * @throws DBUnexpectedError
1269 * @return bool|IResultWrapper
1272 public function delete( $table, $conds, $fname = __METHOD__
);
1275 * INSERT SELECT wrapper. Takes data from a SELECT query and inserts it
1276 * into another table.
1278 * @warning If the insert will use an auto-increment or sequence to
1279 * determine the value of a column, this may break replication on
1280 * databases using statement-based replication if the SELECT is not
1281 * deterministically ordered.
1283 * @param string $destTable The table name to insert into
1284 * @param string|array $srcTable May be either a table name, or an array of table names
1285 * to include in a join.
1287 * @param array $varMap Must be an associative array of the form
1288 * [ 'dest1' => 'source1', ... ]. Source items may be literals
1289 * rather than field names, but strings should be quoted with
1290 * IDatabase::addQuotes()
1292 * @param array $conds Condition array. See $conds in IDatabase::select() for
1293 * the details of the format of condition arrays. May be "*" to copy the
1296 * @param string $fname The function name of the caller, from __METHOD__
1298 * @param array $insertOptions Options for the INSERT part of the query, see
1299 * IDatabase::insert() for details. Also, one additional option is
1300 * available: pass 'NO_AUTO_COLUMNS' to hint that the query does not use
1301 * an auto-increment or sequence to determine any column values.
1302 * @param array $selectOptions Options for the SELECT part of the query, see
1303 * IDatabase::select() for details.
1304 * @param array $selectJoinConds Join conditions for the SELECT part of the query, see
1305 * IDatabase::select() for details.
1310 public function insertSelect( $destTable, $srcTable, $varMap, $conds,
1311 $fname = __METHOD__
,
1312 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
1316 * Returns true if current database backend supports ORDER BY or LIMIT for separate subqueries
1317 * within the UNION construct.
1320 public function unionSupportsOrderAndLimit();
1323 * Construct a UNION query
1324 * This is used for providing overload point for other DB abstractions
1325 * not compatible with the MySQL syntax.
1326 * @param array $sqls SQL statements to combine
1327 * @param bool $all Use UNION ALL
1328 * @return string SQL fragment
1330 public function unionQueries( $sqls, $all );
1333 * Construct a UNION query for permutations of conditions
1335 * Databases sometimes have trouble with queries that have multiple values
1336 * for multiple condition parameters combined with limits and ordering.
1337 * This method constructs queries for the Cartesian product of the
1338 * conditions and unions them all together.
1340 * @see IDatabase::select()
1342 * @param string|array $table Table name
1343 * @param string|array $vars Field names
1344 * @param array $permute_conds Conditions for the Cartesian product. Keys
1345 * are field names, values are arrays of the possible values for that
1347 * @param string|array $extra_conds Additional conditions to include in the
1349 * @param string $fname Caller function name
1350 * @param string|array $options Query options. In addition to the options
1351 * recognized by IDatabase::select(), the following may be used:
1352 * - NOTALL: Set to use UNION instead of UNION ALL.
1353 * - INNER ORDER BY: If specified and supported, subqueries will use this
1354 * instead of ORDER BY.
1355 * @param string|array $join_conds Join conditions
1356 * @return string SQL query string.
1358 public function unionConditionPermutations(
1359 $table, $vars, array $permute_conds, $extra_conds = '', $fname = __METHOD__
,
1360 $options = [], $join_conds = []
1364 * Returns an SQL expression for a simple conditional. This doesn't need
1365 * to be overridden unless CASE isn't supported in your DBMS.
1367 * @param string|array $cond SQL expression which will result in a boolean value
1368 * @param string $trueVal SQL expression to return if true
1369 * @param string $falseVal SQL expression to return if false
1370 * @return string SQL fragment
1372 public function conditional( $cond, $trueVal, $falseVal );
1375 * Returns a command for str_replace function in SQL query.
1376 * Uses REPLACE() in MySQL
1378 * @param string $orig Column to modify
1379 * @param string $old Column to seek
1380 * @param string $new Column to replace with
1384 public function strreplace( $orig, $old, $new );
1387 * Determines how long the server has been up
1392 public function getServerUptime();
1395 * Determines if the last failure was due to a deadlock
1397 * Note that during a deadlock, the prior transaction will have been lost
1401 public function wasDeadlock();
1404 * Determines if the last failure was due to a lock timeout
1406 * Note that during a lock wait timeout, the prior transaction will have been lost
1410 public function wasLockTimeout();
1413 * Determines if the last query error was due to a dropped connection
1415 * Note that during a connection loss, the prior transaction will have been lost
1420 public function wasConnectionLoss();
1423 * Determines if the last failure was due to the database being read-only.
1427 public function wasReadOnlyError();
1430 * Determines if the last query error was due to something outside of the query itself
1432 * Note that the transaction may have been lost, discarding prior writes and results
1436 public function wasErrorReissuable();
1439 * Wait for the replica DB to catch up to a given master position
1441 * @param DBMasterPos $pos
1442 * @param int $timeout The maximum number of seconds to wait for synchronisation
1443 * @return int|null Zero if the replica DB was past that position already,
1444 * greater than zero if we waited for some period of time, less than
1445 * zero if it timed out, and null on error
1448 public function masterPosWait( DBMasterPos
$pos, $timeout );
1451 * Get the replication position of this replica DB
1453 * @return DBMasterPos|bool False if this is not a replica DB
1456 public function getReplicaPos();
1459 * Get the position of this master
1461 * @return DBMasterPos|bool False if this is not a master
1464 public function getMasterPos();
1467 * @return bool Whether the DB is marked as read-only server-side
1470 public function serverIsReadOnly();
1473 * Run a callback as soon as the current transaction commits or rolls back.
1474 * An error is thrown if no transaction is pending. Queries in the function will run in
1475 * AUTO-COMMIT mode unless there are begin() calls. Callbacks must commit any transactions
1478 * This is useful for combining cooperative locks and DB transactions.
1480 * The callback takes one argument:
1481 * - How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK)
1483 * @param callable $callback
1484 * @param string $fname Caller name
1488 public function onTransactionResolution( callable
$callback, $fname = __METHOD__
);
1491 * Run a callback as soon as there is no transaction pending.
1492 * If there is a transaction and it is rolled back, then the callback is cancelled.
1493 * Queries in the function will run in AUTO-COMMIT mode unless there are begin() calls.
1494 * Callbacks must commit any transactions that they begin.
1496 * This is useful for updates to different systems or when separate transactions are needed.
1497 * For example, one might want to enqueue jobs into a system outside the database, but only
1498 * after the database is updated so that the jobs will see the data when they actually run.
1499 * It can also be used for updates that easily cause deadlocks if locks are held too long.
1501 * Updates will execute in the order they were enqueued.
1503 * The callback takes one argument:
1504 * - How the transaction ended (IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_IDLE)
1506 * @param callable $callback
1507 * @param string $fname Caller name
1510 public function onTransactionIdle( callable
$callback, $fname = __METHOD__
);
1513 * Run a callback before the current transaction commits or now if there is none.
1514 * If there is a transaction and it is rolled back, then the callback is cancelled.
1515 * Callbacks must not start nor commit any transactions. If no transaction is active,
1516 * then a transaction will wrap the callback.
1518 * This is useful for updates that easily cause deadlocks if locks are held too long
1519 * but where atomicity is strongly desired for these updates and some related updates.
1521 * Updates will execute in the order they were enqueued.
1523 * @param callable $callback
1524 * @param string $fname Caller name
1527 public function onTransactionPreCommitOrIdle( callable
$callback, $fname = __METHOD__
);
1530 * Run a callback each time any transaction commits or rolls back
1532 * The callback takes two arguments:
1533 * - IDatabase::TRIGGER_COMMIT or IDatabase::TRIGGER_ROLLBACK
1534 * - This IDatabase object
1535 * Callbacks must commit any transactions that they begin.
1537 * Registering a callback here will not affect writesOrCallbacks() pending
1539 * @param string $name Callback name
1540 * @param callable|null $callback Use null to unset a listener
1544 public function setTransactionListener( $name, callable
$callback = null );
1547 * Begin an atomic section of statements
1549 * If a transaction has been started already, (optionally) sets a savepoint
1550 * and tracks the given section name to make sure the transaction is not
1551 * committed pre-maturely. This function can be used in layers (with
1552 * sub-sections), so use a stack to keep track of the different atomic
1553 * sections. If there is no transaction, one is started implicitly.
1555 * The goal of this function is to create an atomic section of SQL queries
1556 * without having to start a new transaction if it already exists.
1558 * All atomic levels *must* be explicitly closed using IDatabase::endAtomic()
1559 * or IDatabase::cancelAtomic(), and any database transactions cannot be
1560 * began or committed until all atomic levels are closed. There is no such
1561 * thing as implicitly opening or closing an atomic section.
1564 * @param string $fname
1565 * @param string $cancelable Pass self::ATOMIC_CANCELABLE to use a
1566 * savepoint and enable self::cancelAtomic() for this section.
1569 public function startAtomic( $fname = __METHOD__
, $cancelable = self
::ATOMIC_NOT_CANCELABLE
);
1572 * Ends an atomic section of SQL statements
1574 * Ends the next section of atomic SQL statements and commits the transaction
1578 * @see IDatabase::startAtomic
1579 * @param string $fname
1582 public function endAtomic( $fname = __METHOD__
);
1585 * Cancel an atomic section of SQL statements
1587 * This will roll back only the statements executed since the start of the
1588 * most recent atomic section, and close that section. If a transaction was
1589 * open before the corresponding startAtomic() call, any statements before
1590 * that call are *not* rolled back and the transaction remains open. If the
1591 * corresponding startAtomic() implicitly started a transaction, that
1592 * transaction is rolled back.
1594 * Note that a call to IDatabase::rollback() will also roll back any open
1597 * @note As a micro-optimization to save a few DB calls, this method may only
1598 * be called when startAtomic() was called with the ATOMIC_CANCELABLE flag.
1600 * @see IDatabase::startAtomic
1601 * @param string $fname
1604 public function cancelAtomic( $fname = __METHOD__
);
1607 * Run a callback to do an atomic set of updates for this database
1609 * The $callback takes the following arguments:
1610 * - This database object
1611 * - The value of $fname
1613 * If any exception occurs in the callback, then cancelAtomic() will be
1614 * called to back out any statements executed by the callback and the error
1615 * will be re-thrown. It may also be that the cancel itself fails with an
1616 * exception before then. In any case, such errors are expected to
1617 * terminate the request, without any outside caller attempting to catch
1618 * errors and commit anyway.
1620 * This can be an alternative to explicit startAtomic()/endAtomic()/cancelAtomic() calls.
1622 * @see Database::startAtomic
1623 * @see Database::endAtomic
1624 * @see Database::cancelAtomic
1626 * @param string $fname Caller name (usually __METHOD__)
1627 * @param callable $callback Callback that issues DB updates
1628 * @return mixed $res Result of the callback (since 1.28)
1630 * @throws RuntimeException
1631 * @throws UnexpectedValueException
1632 * @since 1.27; prior to 1.31 this did a rollback() instead of
1633 * cancelAtomic(), and assumed no callers up the stack would ever try to
1634 * catch the exception.
1636 public function doAtomicSection( $fname, callable
$callback );
1639 * Begin a transaction. If a transaction is already in progress,
1640 * that transaction will be committed before the new transaction is started.
1642 * Only call this from code with outer transcation scope.
1643 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1644 * Nesting of transactions is not supported.
1646 * Note that when the DBO_TRX flag is set (which is usually the case for web
1647 * requests, but not for maintenance scripts), any previous database query
1648 * will have started a transaction automatically.
1650 * Nesting of transactions is not supported. Attempts to nest transactions
1651 * will cause a warning, unless the current transaction was started
1652 * automatically because of the DBO_TRX flag.
1654 * @param string $fname Calling function name
1655 * @param string $mode A situationally valid IDatabase::TRANSACTION_* constant [optional]
1658 public function begin( $fname = __METHOD__
, $mode = self
::TRANSACTION_EXPLICIT
);
1661 * Commits a transaction previously started using begin().
1662 * If no transaction is in progress, a warning is issued.
1664 * Only call this from code with outer transcation scope.
1665 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1666 * Nesting of transactions is not supported.
1668 * @param string $fname
1669 * @param string $flush Flush flag, set to situationally valid IDatabase::FLUSHING_*
1670 * constant to disable warnings about explicitly committing implicit transactions,
1671 * or calling commit when no transaction is in progress.
1673 * This will trigger an exception if there is an ongoing explicit transaction.
1675 * Only set the flush flag if you are sure that these warnings are not applicable,
1676 * and no explicit transactions are open.
1680 public function commit( $fname = __METHOD__
, $flush = '' );
1683 * Rollback a transaction previously started using begin().
1684 * If no transaction is in progress, a warning is issued.
1686 * Only call this from code with outer transcation scope.
1687 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1688 * Nesting of transactions is not supported. If a serious unexpected error occurs,
1689 * throwing an Exception is preferrable, using a pre-installed error handler to trigger
1690 * rollback (in any case, failure to issue COMMIT will cause rollback server-side).
1692 * Query, connection, and onTransaction* callback errors will be suppressed and logged.
1694 * @param string $fname Calling function name
1695 * @param string $flush Flush flag, set to a situationally valid IDatabase::FLUSHING_*
1696 * constant to disable warnings about calling rollback when no transaction is in
1697 * progress. This will silently break any ongoing explicit transaction. Only set the
1698 * flush flag if you are sure that it is safe to ignore these warnings in your context.
1700 * @since 1.23 Added $flush parameter
1702 public function rollback( $fname = __METHOD__
, $flush = '' );
1705 * Commit any transaction but error out if writes or callbacks are pending
1707 * This is intended for clearing out REPEATABLE-READ snapshots so that callers can
1708 * see a new point-in-time of the database. This is useful when one of many transaction
1709 * rounds finished and significant time will pass in the script's lifetime. It is also
1710 * useful to call on a replica DB after waiting on replication to catch up to the master.
1712 * @param string $fname Calling function name
1716 public function flushSnapshot( $fname = __METHOD__
);
1719 * Convert a timestamp in one of the formats accepted by wfTimestamp()
1720 * to the format used for inserting into timestamp fields in this DBMS.
1722 * The result is unquoted, and needs to be passed through addQuotes()
1723 * before it can be included in raw SQL.
1725 * @param string|int $ts
1729 public function timestamp( $ts = 0 );
1732 * Convert a timestamp in one of the formats accepted by wfTimestamp()
1733 * to the format used for inserting into timestamp fields in this DBMS. If
1734 * NULL is input, it is passed through, allowing NULL values to be inserted
1735 * into timestamp fields.
1737 * The result is unquoted, and needs to be passed through addQuotes()
1738 * before it can be included in raw SQL.
1740 * @param string|int $ts
1744 public function timestampOrNull( $ts = null );
1747 * Ping the server and try to reconnect if it there is no connection
1749 * @param float|null &$rtt Value to store the estimated RTT [optional]
1750 * @return bool Success or failure
1752 public function ping( &$rtt = null );
1755 * Get replica DB lag. Currently supported only by MySQL.
1757 * Note that this function will generate a fatal error on many
1758 * installations. Most callers should use LoadBalancer::safeGetLag()
1761 * @return int|bool Database replication lag in seconds or false on error
1764 public function getLag();
1767 * Get the replica DB lag when the current transaction started
1768 * or a general lag estimate if not transaction is active
1770 * This is useful when transactions might use snapshot isolation
1771 * (e.g. REPEATABLE-READ in innodb), so the "real" lag of that data
1772 * is this lag plus transaction duration. If they don't, it is still
1773 * safe to be pessimistic. In AUTO-COMMIT mode, this still gives an
1774 * indication of the staleness of subsequent reads.
1776 * @return array ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
1780 public function getSessionLagStatus();
1783 * Return the maximum number of items allowed in a list, or 0 for unlimited.
1787 public function maxListLen();
1790 * Some DBMSs have a special format for inserting into blob fields, they
1791 * don't allow simple quoted strings to be inserted. To insert into such
1792 * a field, pass the data through this function before passing it to
1793 * IDatabase::insert().
1796 * @return string|Blob
1798 public function encodeBlob( $b );
1801 * Some DBMSs return a special placeholder object representing blob fields
1802 * in result objects. Pass the object through this function to return the
1805 * @param string|Blob $b
1808 public function decodeBlob( $b );
1811 * Override database's default behavior. $options include:
1812 * 'connTimeout' : Set the connection timeout value in seconds.
1813 * May be useful for very long batch queries such as
1814 * full-wiki dumps, where a single query reads out over
1817 * @param array $options
1821 public function setSessionOptions( array $options );
1824 * Set variables to be used in sourceFile/sourceStream, in preference to the
1825 * ones in $GLOBALS. If an array is set here, $GLOBALS will not be used at
1826 * all. If it's set to false, $GLOBALS will be used.
1828 * @param bool|array $vars Mapping variable name to value.
1830 public function setSchemaVars( $vars );
1833 * Check to see if a named lock is not locked by any thread (non-blocking)
1835 * @param string $lockName Name of lock to poll
1836 * @param string $method Name of method calling us
1841 public function lockIsFree( $lockName, $method );
1844 * Acquire a named lock
1846 * Named locks are not related to transactions
1848 * @param string $lockName Name of lock to aquire
1849 * @param string $method Name of the calling method
1850 * @param int $timeout Acquisition timeout in seconds
1854 public function lock( $lockName, $method, $timeout = 5 );
1859 * Named locks are not related to transactions
1861 * @param string $lockName Name of lock to release
1862 * @param string $method Name of the calling method
1864 * @return int Returns 1 if the lock was released, 0 if the lock was not established
1865 * by this thread (in which case the lock is not released), and NULL if the named lock
1870 public function unlock( $lockName, $method );
1873 * Acquire a named lock, flush any transaction, and return an RAII style unlocker object
1875 * Only call this from outer transcation scope and when only one DB will be affected.
1876 * See https://www.mediawiki.org/wiki/Database_transactions for details.
1878 * This is suitiable for transactions that need to be serialized using cooperative locks,
1879 * where each transaction can see each others' changes. Any transaction is flushed to clear
1880 * out stale REPEATABLE-READ snapshot data. Once the returned object falls out of PHP scope,
1881 * the lock will be released unless a transaction is active. If one is active, then the lock
1882 * will be released when it either commits or rolls back.
1884 * If the lock acquisition failed, then no transaction flush happens, and null is returned.
1886 * @param string $lockKey Name of lock to release
1887 * @param string $fname Name of the calling method
1888 * @param int $timeout Acquisition timeout in seconds
1889 * @return ScopedCallback|null
1893 public function getScopedLockAndFlush( $lockKey, $fname, $timeout );
1896 * Check to see if a named lock used by lock() use blocking queues
1901 public function namedLocksEnqueue();
1904 * Find out when 'infinity' is. Most DBMSes support this. This is a special
1905 * keyword for timestamps in PostgreSQL, and works with CHAR(14) as well
1906 * because "i" sorts after all numbers.
1910 public function getInfinity();
1913 * Encode an expiry time into the DBMS dependent format
1915 * @param string $expiry Timestamp for expiry, or the 'infinity' string
1918 public function encodeExpiry( $expiry );
1921 * Decode an expiry time into a DBMS independent format
1923 * @param string $expiry DB timestamp field value for expiry
1924 * @param int $format TS_* constant, defaults to TS_MW
1927 public function decodeExpiry( $expiry, $format = TS_MW
);
1930 * Allow or deny "big selects" for this session only. This is done by setting
1931 * the sql_big_selects session variable.
1933 * This is a MySQL-specific feature.
1935 * @param bool|string $value True for allow, false for deny, or "default" to
1936 * restore the initial value
1938 public function setBigSelects( $value = true );
1941 * @return bool Whether this DB is read-only
1944 public function isReadOnly();
1947 * Make certain table names use their own database, schema, and table prefix
1948 * when passed into SQL queries pre-escaped and without a qualified database name
1950 * For example, "user" can be converted to "myschema.mydbname.user" for convenience.
1951 * Appearances like `user`, somedb.user, somedb.someschema.user will used literally.
1953 * Calling this twice will completely clear any old table aliases. Also, note that
1954 * callers are responsible for making sure the schemas and databases actually exist.
1956 * @param array[] $aliases Map of (table => (dbname, schema, prefix) map)
1959 public function setTableAliases( array $aliases );
1962 * Convert certain index names to alternative names before querying the DB
1964 * Note that this applies to indexes regardless of the table they belong to.
1966 * This can be employed when an index was renamed X => Y in code, but the new Y-named
1967 * indexes were not yet built on all DBs. After all the Y-named ones are added by the DBA,
1968 * the aliases can be removed, and then the old X-named indexes dropped.
1970 * @param string[] $aliases
1974 public function setIndexAliases( array $aliases );
1977 class_alias( IDatabase
::class, 'IDatabase' );