includes/Database.php

   1 <?php
   2 /**
   3  * This file deals with MySQL interface functions
   4  * and query specifics/optimisations
   5  * @package MediaWiki
   6  */
   7
   8 /** Number of times to re-try an operation in case of deadlock */
   9 define( 'DEADLOCK_TRIES', 4 );
  10 /** Minimum time to wait before retry, in microseconds */
  11 define( 'DEADLOCK_DELAY_MIN', 500000 );
  12 /** Maximum time to wait before retry */
  13 define( 'DEADLOCK_DELAY_MAX', 1500000 );
  14
  15 /******************************************************************************
  16  * Utility classes
  17  *****************************************************************************/
  18
  19 class DBObject {
  20         public $mData;
  21
  22         function DBObject($data) {
  23                 $this->mData = $data;
  24         }
  25
  26         function isLOB() {
  27                 return false;
  28         }
  29
  30         function data() {
  31                 return $this->mData;
  32         }
  33 };
  34
  35 /******************************************************************************
  36  * Error classes
  37  *****************************************************************************/
  38
  39 /**
  40  * Database error base class
  41  */
  42 class DBError extends MWException {
  43         public $db;
  44
  45         /**
  46          * Construct a database error
  47          * @param Database $db The database object which threw the error
  48          * @param string $error A simple error message to be used for debugging
  49          */
  50         function __construct( Database &$db, $error ) {
  51                 $this->db =& $db;
  52                 parent::__construct( $error );
  53         }
  54 }
  55
  56 class DBConnectionError extends DBError {
  57         public $error;
  58
  59         function __construct( Database &$db, $error = 'unknown error' ) {
  60                 $msg = 'DB connection error';
  61                 if ( trim( $error ) != '' ) {
  62                         $msg .= ": $error";
  63                 }
  64                 $this->error = $error;
  65                 parent::__construct( $db, $msg );
  66         }
  67
  68         function useOutputPage() {
  69                 // Not likely to work
  70                 return false;
  71         }
  72
  73         function useMessageCache() {
  74                 // Not likely to work
  75                 return false;
  76         }
  77
  78         function getText() {
  79                 return $this->getMessage() . "\n";
  80         }
  81
  82         function getLogMessage() {
  83                 # Don't send to the exception log
  84                 return false;
  85         }
  86
  87         function getPageTitle() {
  88                 global $wgSitename;
  89                 return "$wgSitename has a problem";
  90         }
  91
  92         function getHTML() {
  93                 global $wgTitle, $wgUseFileCache, $title, $wgInputEncoding;
  94                 global $wgSitename, $wgServer, $wgMessageCache;
  95
  96                 # I give up, Brion is right. Getting the message cache to work when there is no DB is tricky.
  97                 # Hard coding strings instead.
  98
  99                 $noconnect = "<p><strong>Sorry! This site is experiencing technical difficulties.</strong></p><p>Try waiting a few minutes and reloading.</p><p><small>(Can't contact the database server: $1)</small></p>";
 100                 $mainpage = 'Main Page';
 101                 $searchdisabled = <<<EOT
 102 <p style="margin: 1.5em 2em 1em">$wgSitename search is disabled for performance reasons. You can search via Google in the meantime.
 103 <span style="font-size: 89%; display: block; margin-left: .2em">Note that their indexes of $wgSitename content may be out of date.</span></p>',
 104 EOT;
 105
 106                 $googlesearch = "
 107 <!-- SiteSearch Google -->
 108 <FORM method=GET action=\"http://www.google.com/search\">
 109 <TABLE bgcolor=\"#FFFFFF\"><tr><td>
 110 <A HREF=\"http://www.google.com/\">
 111 <IMG SRC=\"http://www.google.com/logos/Logo_40wht.gif\"
 112 border=\"0\" ALT=\"Google\"></A>
 113 </td>
 114 <td>
 115 <INPUT TYPE=text name=q size=31 maxlength=255 value=\"$1\">
 116 <INPUT type=submit name=btnG VALUE=\"Google Search\">
 117 <font size=-1>
 118 <input type=hidden name=domains value=\"$wgServer\"><br /><input type=radio name=sitesearch value=\"\"> WWW <input type=radio name=sitesearch value=\"$wgServer\" checked> $wgServer <br />
 119 <input type='hidden' name='ie' value='$2'>
 120 <input type='hidden' name='oe' value='$2'>
 121 </font>
 122 </td></tr></TABLE>
 123 </FORM>
 124 <!-- SiteSearch Google -->";
 125                 $cachederror = "The following is a cached copy of the requested page, and may not be up to date. ";
 126
 127                 # No database access
 128                 if ( is_object( $wgMessageCache ) ) {
 129                         $wgMessageCache->disable();
 130                 }
 131
 132                 if ( trim( $this->error ) == '' ) {
 133                         $this->error = $this->db->getProperty('mServer');
 134                 }
 135
 136                 $text = str_replace( '$1', $this->error, $noconnect );
 137                 $text .= wfGetSiteNotice();
 138
 139                 if($wgUseFileCache) {
 140                         if($wgTitle) {
 141                                 $t =& $wgTitle;
 142                         } else {
 143                                 if($title) {
 144                                         $t = Title::newFromURL( $title );
 145                                 } elseif (@/**/$_REQUEST['search']) {
 146                                         $search = $_REQUEST['search'];
 147                                         return $searchdisabled .
 148                                           str_replace( array( '$1', '$2' ), array( htmlspecialchars( $search ),
 149                                           $wgInputEncoding ), $googlesearch );
 150                                 } else {
 151                                         $t = Title::newFromText( $mainpage );
 152                                 }
 153                         }
 154
 155                         $cache = new HTMLFileCache( $t );
 156                         if( $cache->isFileCached() ) {
 157                                 $msg = '<p style="color: red"><b>'.$msg."<br />\n" .
 158                                         $cachederror . "</b></p>\n";
 159
 160                                 $tag = '<div id="article">';
 161                                 $text = str_replace(
 162                                         $tag,
 163                                         $tag . $msg,
 164                                         $cache->fetchPageText() );
 165                         }
 166                 }
 167
 168                 return $text;
 169         }
 170 }
 171
 172 class DBQueryError extends DBError {
 173         public $error, $errno, $sql, $fname;
 174
 175         function __construct( Database &$db, $error, $errno, $sql, $fname ) {
 176                 $message = "A database error has occurred\n" .
 177                   "Query: $sql\n" .
 178                   "Function: $fname\n" .
 179                   "Error: $errno $error\n";
 180
 181                 parent::__construct( $db, $message );
 182                 $this->error = $error;
 183                 $this->errno = $errno;
 184                 $this->sql = $sql;
 185                 $this->fname = $fname;
 186         }
 187
 188         function getText() {
 189                 if ( $this->useMessageCache() ) {
 190                         return wfMsg( 'dberrortextcl', htmlspecialchars( $this->getSQL() ),
 191                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) ) . "\n";
 192                 } else {
 193                         return $this->getMessage();
 194                 }
 195         }
 196
 197         function getSQL() {
 198                 global $wgShowSQLErrors;
 199                 if( !$wgShowSQLErrors ) {
 200                         return $this->msg( 'sqlhidden', 'SQL hidden' );
 201                 } else {
 202                         return $this->sql;
 203                 }
 204         }
 205
 206         function getLogMessage() {
 207                 # Don't send to the exception log
 208                 return false;
 209         }
 210
 211         function getPageTitle() {
 212                 return $this->msg( 'databaseerror', 'Database error' );
 213         }
 214
 215         function getHTML() {
 216                 if ( $this->useMessageCache() ) {
 217                         return wfMsgNoDB( 'dberrortext', htmlspecialchars( $this->getSQL() ),
 218                           htmlspecialchars( $this->fname ), $this->errno, htmlspecialchars( $this->error ) );
 219                 } else {
 220                         return nl2br( htmlspecialchars( $this->getMessage() ) );
 221                 }
 222         }
 223 }
 224
 225 class DBUnexpectedError extends DBError {}
 226
 227 /******************************************************************************/
 228
 229 /**
 230  * Database abstraction object
 231  * @package MediaWiki
 232  */
 233 class Database {
 234
 235 #------------------------------------------------------------------------------
 236 # Variables
 237 #------------------------------------------------------------------------------
 238
 239         protected $mLastQuery = '';
 240
 241         protected $mServer, $mUser, $mPassword, $mConn = null, $mDBname;
 242         protected $mOut, $mOpened = false;
 243
 244         protected $mFailFunction;
 245         protected $mTablePrefix;
 246         protected $mFlags;
 247         protected $mTrxLevel = 0;
 248         protected $mErrorCount = 0;
 249         protected $mLBInfo = array();
 250         protected $mCascadingDeletes = false;
 251         protected $mCleanupTriggers = false;
 252         protected $mStrictIPs = false;
 253
 254 #------------------------------------------------------------------------------
 255 # Accessors
 256 #------------------------------------------------------------------------------
 257         # These optionally set a variable and return the previous state
 258
 259         /**
 260          * Fail function, takes a Database as a parameter
 261          * Set to false for default, 1 for ignore errors
 262          */
 263         function failFunction( $function = NULL ) {
 264                 return wfSetVar( $this->mFailFunction, $function );
 265         }
 266
 267         /**
 268          * Output page, used for reporting errors
 269          * FALSE means discard output
 270          */
 271         function setOutputPage( $out ) {
 272                 $this->mOut = $out;
 273         }
 274
 275         /**
 276          * Boolean, controls output of large amounts of debug information
 277          */
 278         function debug( $debug = NULL ) {
 279                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
 280         }
 281
 282         /**
 283          * Turns buffering of SQL result sets on (true) or off (false).
 284          * Default is "on" and it should not be changed without good reasons.
 285          */
 286         function bufferResults( $buffer = NULL ) {
 287                 if ( is_null( $buffer ) ) {
 288                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
 289                 } else {
 290                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
 291                 }
 292         }
 293
 294         /**
 295          * Turns on (false) or off (true) the automatic generation and sending
 296          * of a "we're sorry, but there has been a database error" page on
 297          * database errors. Default is on (false). When turned off, the
 298          * code should use lastErrno() and lastError() to handle the
 299          * situation as appropriate.
 300          */
 301         function ignoreErrors( $ignoreErrors = NULL ) {
 302                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
 303         }
 304
 305         /**
 306          * The current depth of nested transactions
 307          * @param $level Integer: , default NULL.
 308          */
 309         function trxLevel( $level = NULL ) {
 310                 return wfSetVar( $this->mTrxLevel, $level );
 311         }
 312
 313         /**
 314          * Number of errors logged, only useful when errors are ignored
 315          */
 316         function errorCount( $count = NULL ) {
 317                 return wfSetVar( $this->mErrorCount, $count );
 318         }
 319
 320         /**
 321          * Properties passed down from the server info array of the load balancer
 322          */
 323         function getLBInfo( $name = NULL ) {
 324                 if ( is_null( $name ) ) {
 325                         return $this->mLBInfo;
 326                 } else {
 327                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 328                                 return $this->mLBInfo[$name];
 329                         } else {
 330                                 return NULL;
 331                         }
 332                 }
 333         }
 334
 335         function setLBInfo( $name, $value = NULL ) {
 336                 if ( is_null( $value ) ) {
 337                         $this->mLBInfo = $name;
 338                 } else {
 339                         $this->mLBInfo[$name] = $value;
 340                 }
 341         }
 342
 343         /**
 344          * Returns true if this database supports (and uses) cascading deletes
 345          */
 346         function cascadingDeletes() {
 347                 return $this->mCascadingDeletes;
 348         }
 349
 350         /**
 351          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 352          */
 353         function cleanupTriggers() {
 354                 return $this->mCleanupTriggers;
 355         }
 356
 357         /**
 358          * Returns true if this database is strict about what can be put into an IP field.
 359          * Specifically, it uses a NULL value instead of an empty string.
 360          */
 361         function strictIPs() {
 362                 return $this->mStrictIPs;
 363         }
 364
 365         /**
 366          * Returns true if this database uses timestamps rather than integers
 367         */
 368         function realTimestamps() {
 369                 return false;
 370         }
 371
 372         /**
 373          * Returns true if this database does an implicit sort when doing GROUP BY
 374          */
 375         function implicitGroupby() {
 376                 return true;
 377         }
 378
 379         /**#@+
 380          * Get function
 381          */
 382         function lastQuery() { return $this->mLastQuery; }
 383         function isOpen() { return $this->mOpened; }
 384         /**#@-*/
 385
 386         function setFlag( $flag ) {
 387                 $this->mFlags |= $flag;
 388         }
 389
 390         function clearFlag( $flag ) {
 391                 $this->mFlags &= ~$flag;
 392         }
 393
 394         function getFlag( $flag ) {
 395                 return !!($this->mFlags & $flag);
 396         }
 397
 398         /**
 399          * General read-only accessor
 400          */
 401         function getProperty( $name ) {
 402                 return $this->$name;
 403         }
 404
 405 #------------------------------------------------------------------------------
 406 # Other functions
 407 #------------------------------------------------------------------------------
 408
 409         /**@{{
 410          * @param string $server database server host
 411          * @param string $user database user name
 412          * @param string $password database user password
 413          * @param string $dbname database name
 414          */
 415
 416         /**
 417          * @param failFunction
 418          * @param $flags
 419          * @param $tablePrefix String: database table prefixes. By default use the prefix gave in LocalSettings.php
 420          */
 421         function __construct( $server = false, $user = false, $password = false, $dbName = false,
 422                 $failFunction = false, $flags = 0, $tablePrefix = 'get from global' ) {
 423
 424                 global $wgOut, $wgDBprefix, $wgCommandLineMode;
 425                 # Can't get a reference if it hasn't been set yet
 426                 if ( !isset( $wgOut ) ) {
 427                         $wgOut = NULL;
 428                 }
 429                 $this->mOut =& $wgOut;
 430
 431                 $this->mFailFunction = $failFunction;
 432                 $this->mFlags = $flags;
 433
 434                 if ( $this->mFlags & DBO_DEFAULT ) {
 435                         if ( $wgCommandLineMode ) {
 436                                 $this->mFlags &= ~DBO_TRX;
 437                         } else {
 438                                 $this->mFlags |= DBO_TRX;
 439                         }
 440                 }
 441
 442                 /*
 443                 // Faster read-only access
 444                 if ( wfReadOnly() ) {
 445                         $this->mFlags |= DBO_PERSISTENT;
 446                         $this->mFlags &= ~DBO_TRX;
 447                 }*/
 448
 449                 /** Get the default table prefix*/
 450                 if ( $tablePrefix == 'get from global' ) {
 451                         $this->mTablePrefix = $wgDBprefix;
 452                 } else {
 453                         $this->mTablePrefix = $tablePrefix;
 454                 }
 455
 456                 if ( $server ) {
 457                         $this->open( $server, $user, $password, $dbName );
 458                 }
 459         }
 460
 461         /**
 462          * @static
 463          * @param failFunction
 464          * @param $flags
 465          */
 466         static function newFromParams( $server, $user, $password, $dbName,
 467                 $failFunction = false, $flags = 0 )
 468         {
 469                 return new Database( $server, $user, $password, $dbName, $failFunction, $flags );
 470         }
 471
 472         /**
 473          * Usually aborts on failure
 474          * If the failFunction is set to a non-zero integer, returns success
 475          */
 476         function open( $server, $user, $password, $dbName ) {
 477                 global $wguname;
 478                 wfProfileIn( __METHOD__ );
 479
 480                 # Test for missing mysql.so
 481                 # First try to load it
 482                 if (!@extension_loaded('mysql')) {
 483                         @dl('mysql.so');
 484                 }
 485
 486                 # Fail now
 487                 # Otherwise we get a suppressed fatal error, which is very hard to track down
 488                 if ( !function_exists( 'mysql_connect' ) ) {
 489                         throw new DBConnectionError( $this, "MySQL functions missing, have you compiled PHP with the --with-mysql option?\n" );
 490                 }
 491
 492                 $this->close();
 493                 $this->mServer = $server;
 494                 $this->mUser = $user;
 495                 $this->mPassword = $password;
 496                 $this->mDBname = $dbName;
 497
 498                 $success = false;
 499
 500                 wfProfileIn("dbconnect-$server");
 501
 502                 # LIVE PATCH by Tim, ask Domas for why: retry loop
 503                 $this->mConn = false;
 504                 $max = 3;
 505                 for ( $i = 0; $i < $max && !$this->mConn; $i++ ) {
 506                         if ( $i > 1 ) {
 507                                 usleep( 1000 );
 508                         }
 509                         if ( $this->mFlags & DBO_PERSISTENT ) {
 510                                 @/**/$this->mConn = mysql_pconnect( $server, $user, $password );
 511                         } else {
 512                                 # Create a new connection...
 513                                 @/**/$this->mConn = mysql_connect( $server, $user, $password, true );
 514                         }
 515                         if ($this->mConn === false) {
 516                                 $iplus = $i + 1;
 517                                 wfLogDBError("Connect loop error $iplus of $max ($server): " . mysql_errno() . " - " . mysql_error()."\n");
 518                         }
 519                 }
 520
 521                 wfProfileOut("dbconnect-$server");
 522
 523                 if ( $dbName != '' ) {
 524                         if ( $this->mConn !== false ) {
 525                                 $success = @/**/mysql_select_db( $dbName, $this->mConn );
 526                                 if ( !$success ) {
 527                                         $error = "Error selecting database $dbName on server {$this->mServer} " .
 528                                                 "from client host {$wguname['nodename']}\n";
 529                                         wfLogDBError(" Error selecting database $dbName on server {$this->mServer} \n");
 530                                         wfDebug( $error );
 531                                 }
 532                         } else {
 533                                 wfDebug( "DB connection error\n" );
 534                                 wfDebug( "Server: $server, User: $user, Password: " .
 535                                         substr( $password, 0, 3 ) . "..., error: " . mysql_error() . "\n" );
 536                                 $success = false;
 537                         }
 538                 } else {
 539                         # Delay USE query
 540                         $success = (bool)$this->mConn;
 541                 }
 542
 543                 if ( $success ) {
 544                         global $wgDBmysql5;
 545                         if( $wgDBmysql5 ) {
 546                                 // Tell the server we're communicating with it in UTF-8.
 547                                 // This may engage various charset conversions.
 548                                 $this->query( 'SET NAMES utf8' );
 549                         }
 550                 } else {
 551                         $this->reportConnectionError();
 552                 }
 553
 554                 $this->mOpened = $success;
 555                 wfProfileOut( __METHOD__ );
 556                 return $success;
 557         }
 558         /**@}}*/
 559
 560         /**
 561          * Closes a database connection.
 562          * if it is open : commits any open transactions
 563          *
 564          * @return bool operation success. true if already closed.
 565          */
 566         function close()
 567         {
 568                 $this->mOpened = false;
 569                 if ( $this->mConn ) {
 570                         if ( $this->trxLevel() ) {
 571                                 $this->immediateCommit();
 572                         }
 573                         return mysql_close( $this->mConn );
 574                 } else {
 575                         return true;
 576                 }
 577         }
 578
 579         /**
 580          * @param string $error fallback error message, used if none is given by MySQL
 581          */
 582         function reportConnectionError( $error = 'Unknown error' ) {
 583                 $myError = $this->lastError();
 584                 if ( $myError ) {
 585                         $error = $myError;
 586                 }
 587
 588                 if ( $this->mFailFunction ) {
 589                         # Legacy error handling method
 590                         if ( !is_int( $this->mFailFunction ) ) {
 591                                 $ff = $this->mFailFunction;
 592                                 $ff( $this, $error );
 593                         }
 594                 } else {
 595                         # New method
 596                         wfLogDBError( "Connection error: $error\n" );
 597                         throw new DBConnectionError( $this, $error );
 598                 }
 599         }
 600
 601         /**
 602          * Usually aborts on failure
 603          * If errors are explicitly ignored, returns success
 604          */
 605         function query( $sql, $fname = '', $tempIgnore = false ) {
 606                 global $wgProfiling;
 607
 608                 if ( $wgProfiling ) {
 609                         # generalizeSQL will probably cut down the query to reasonable
 610                         # logging size most of the time. The substr is really just a sanity check.
 611
 612                         # Who's been wasting my precious column space? -- TS
 613                         #$profName = 'query: ' . $fname . ' ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 614
 615                         if ( is_null( $this->getLBInfo( 'master' ) ) ) {
 616                                 $queryProf = 'query: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 617                                 $totalProf = 'Database::query';
 618                         } else {
 619                                 $queryProf = 'query-m: ' . substr( Database::generalizeSQL( $sql ), 0, 255 );
 620                                 $totalProf = 'Database::query-master';
 621                         }
 622                         wfProfileIn( $totalProf );
 623                         wfProfileIn( $queryProf );
 624                 }
 625
 626                 $this->mLastQuery = $sql;
 627
 628                 # Add a comment for easy SHOW PROCESSLIST interpretation
 629                 if ( $fname ) {
 630                         $commentedSql = preg_replace('/\s/', " /* $fname */ ", $sql, 1);
 631                 } else {
 632                         $commentedSql = $sql;
 633                 }
 634
 635                 # If DBO_TRX is set, start a transaction
 636                 if ( ( $this->mFlags & DBO_TRX ) && !$this->trxLevel() &&
 637                         $sql != 'BEGIN' && $sql != 'COMMIT' && $sql != 'ROLLBACK'
 638                 ) {
 639                         $this->begin();
 640                 }
 641
 642                 if ( $this->debug() ) {
 643                         $sqlx = substr( $commentedSql, 0, 500 );
 644                         $sqlx = strtr( $sqlx, "\t\n", '  ' );
 645                         wfDebug( "SQL: $sqlx\n" );
 646                 }
 647
 648                 # Do the query and handle errors
 649                 $ret = $this->doQuery( $commentedSql );
 650
 651                 # Try reconnecting if the connection was lost
 652                 if ( false === $ret && ( $this->lastErrno() == 2013 || $this->lastErrno() == 2006 ) ) {
 653                         # Transaction is gone, like it or not
 654                         $this->mTrxLevel = 0;
 655                         wfDebug( "Connection lost, reconnecting...\n" );
 656                         if ( $this->ping() ) {
 657                                 wfDebug( "Reconnected\n" );
 658                                 $ret = $this->doQuery( $commentedSql );
 659                         } else {
 660                                 wfDebug( "Failed\n" );
 661                         }
 662                 }
 663
 664                 if ( false === $ret ) {
 665                         $this->reportQueryError( $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 666                 }
 667
 668                 if ( $wgProfiling ) {
 669                         wfProfileOut( $queryProf );
 670                         wfProfileOut( $totalProf );
 671                 }
 672                 return $ret;
 673         }
 674
 675         /**
 676          * The DBMS-dependent part of query()
 677          * @param string $sql SQL query.
 678          */
 679         function doQuery( $sql ) {
 680                 if( $this->bufferResults() ) {
 681                         $ret = mysql_query( $sql, $this->mConn );
 682                 } else {
 683                         $ret = mysql_unbuffered_query( $sql, $this->mConn );
 684                 }
 685                 return $ret;
 686         }
 687
 688         /**
 689          * @param $error
 690          * @param $errno
 691          * @param $sql
 692          * @param string $fname
 693          * @param bool $tempIgnore
 694          */
 695         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 696                 global $wgCommandLineMode;
 697                 # Ignore errors during error handling to avoid infinite recursion
 698                 $ignore = $this->ignoreErrors( true );
 699                 ++$this->mErrorCount;
 700
 701                 if( $ignore || $tempIgnore ) {
 702                         wfDebug("SQL ERROR (ignored): $error\n");
 703                         $this->ignoreErrors( $ignore );
 704                 } else {
 705                         $sql1line = str_replace( "\n", "\\n", $sql );
 706                         wfLogDBError("$fname\t{$this->mServer}\t$errno\t$error\t$sql1line\n");
 707                         wfDebug("SQL ERROR: " . $error . "\n");
 708                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
 709                 }
 710         }
 711
 712
 713         /**
 714          * Intended to be compatible with the PEAR::DB wrapper functions.
 715          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
 716          *
 717          * ? = scalar value, quoted as necessary
 718          * ! = raw SQL bit (a function for instance)
 719          * & = filename; reads the file and inserts as a blob
 720          *     (we don't use this though...)
 721          */
 722         function prepare( $sql, $func = 'Database::prepare' ) {
 723                 /* MySQL doesn't support prepared statements (yet), so just
 724                    pack up the query for reference. We'll manually replace
 725                    the bits later. */
 726                 return array( 'query' => $sql, 'func' => $func );
 727         }
 728
 729         function freePrepared( $prepared ) {
 730                 /* No-op for MySQL */
 731         }
 732
 733         /**
 734          * Execute a prepared query with the various arguments
 735          * @param string $prepared the prepared sql
 736          * @param mixed $args Either an array here, or put scalars as varargs
 737          */
 738         function execute( $prepared, $args = null ) {
 739                 if( !is_array( $args ) ) {
 740                         # Pull the var args
 741                         $args = func_get_args();
 742                         array_shift( $args );
 743                 }
 744                 $sql = $this->fillPrepared( $prepared['query'], $args );
 745                 return $this->query( $sql, $prepared['func'] );
 746         }
 747
 748         /**
 749          * Prepare & execute an SQL statement, quoting and inserting arguments
 750          * in the appropriate places.
 751          * @param string $query
 752          * @param string $args ...
 753          */
 754         function safeQuery( $query, $args = null ) {
 755                 $prepared = $this->prepare( $query, 'Database::safeQuery' );
 756                 if( !is_array( $args ) ) {
 757                         # Pull the var args
 758                         $args = func_get_args();
 759                         array_shift( $args );
 760                 }
 761                 $retval = $this->execute( $prepared, $args );
 762                 $this->freePrepared( $prepared );
 763                 return $retval;
 764         }
 765
 766         /**
 767          * For faking prepared SQL statements on DBs that don't support
 768          * it directly.
 769          * @param string $preparedSql - a 'preparable' SQL statement
 770          * @param array $args - array of arguments to fill it with
 771          * @return string executable SQL
 772          */
 773         function fillPrepared( $preparedQuery, $args ) {
 774                 reset( $args );
 775                 $this->preparedArgs =& $args;
 776                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
 777                         array( &$this, 'fillPreparedArg' ), $preparedQuery );
 778         }
 779
 780         /**
 781          * preg_callback func for fillPrepared()
 782          * The arguments should be in $this->preparedArgs and must not be touched
 783          * while we're doing this.
 784          *
 785          * @param array $matches
 786          * @return string
 787          * @private
 788          */
 789         function fillPreparedArg( $matches ) {
 790                 switch( $matches[1] ) {
 791                         case '\\?': return '?';
 792                         case '\\!': return '!';
 793                         case '\\&': return '&';
 794                 }
 795                 list( /* $n */ , $arg ) = each( $this->preparedArgs );
 796                 switch( $matches[1] ) {
 797                         case '?': return $this->addQuotes( $arg );
 798                         case '!': return $arg;
 799                         case '&':
 800                                 # return $this->addQuotes( file_get_contents( $arg ) );
 801                                 throw new DBUnexpectedError( $this, '& mode is not implemented. If it\'s really needed, uncomment the line above.' );
 802                         default:
 803                                 throw new DBUnexpectedError( $this, 'Received invalid match. This should never happen!' );
 804                 }
 805         }
 806
 807         /**#@+
 808          * @param mixed $res A SQL result
 809          */
 810         /**
 811          * Free a result object
 812          */
 813         function freeResult( $res ) {
 814                 if ( !@/**/mysql_free_result( $res ) ) {
 815                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 816                 }
 817         }
 818
 819         /**
 820          * Fetch the next row from the given result object, in object form
 821          */
 822         function fetchObject( $res ) {
 823                 @/**/$row = mysql_fetch_object( $res );
 824                 if( $this->lastErrno() ) {
 825                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 826                 }
 827                 return $row;
 828         }
 829
 830         /**
 831          * Fetch the next row from the given result object
 832          * Returns an array
 833          */
 834         function fetchRow( $res ) {
 835                 @/**/$row = mysql_fetch_array( $res );
 836                 if ( $this->lastErrno() ) {
 837                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 838                 }
 839                 return $row;
 840         }
 841
 842         /**
 843          * Get the number of rows in a result object
 844          */
 845         function numRows( $res ) {
 846                 @/**/$n = mysql_num_rows( $res );
 847                 if( $this->lastErrno() ) {
 848                         throw new DBUnexpectedError( $this, 'Error in numRows(): ' . htmlspecialchars( $this->lastError() ) );
 849                 }
 850                 return $n;
 851         }
 852
 853         /**
 854          * Get the number of fields in a result object
 855          * See documentation for mysql_num_fields()
 856          */
 857         function numFields( $res ) { return mysql_num_fields( $res ); }
 858
 859         /**
 860          * Get a field name in a result object
 861          * See documentation for mysql_field_name():
 862          * http://www.php.net/mysql_field_name
 863          */
 864         function fieldName( $res, $n ) { return mysql_field_name( $res, $n ); }
 865
 866         /**
 867          * Get the inserted value of an auto-increment row
 868          *
 869          * The value inserted should be fetched from nextSequenceValue()
 870          *
 871          * Example:
 872          * $id = $dbw->nextSequenceValue('page_page_id_seq');
 873          * $dbw->insert('page',array('page_id' => $id));
 874          * $id = $dbw->insertId();
 875          */
 876         function insertId() { return mysql_insert_id( $this->mConn ); }
 877
 878         /**
 879          * Change the position of the cursor in a result object
 880          * See mysql_data_seek()
 881          */
 882         function dataSeek( $res, $row ) { return mysql_data_seek( $res, $row ); }
 883
 884         /**
 885          * Get the last error number
 886          * See mysql_errno()
 887          */
 888         function lastErrno() {
 889                 if ( $this->mConn ) {
 890                         return mysql_errno( $this->mConn );
 891                 } else {
 892                         return mysql_errno();
 893                 }
 894         }
 895
 896         /**
 897          * Get a description of the last error
 898          * See mysql_error() for more details
 899          */
 900         function lastError() {
 901                 if ( $this->mConn ) {
 902                         # Even if it's non-zero, it can still be invalid
 903                         wfSuppressWarnings();
 904                         $error = mysql_error( $this->mConn );
 905                         if ( !$error ) {
 906                                 $error = mysql_error();
 907                         }
 908                         wfRestoreWarnings();
 909                 } else {
 910                         $error = mysql_error();
 911                 }
 912                 if( $error ) {
 913                         $error .= ' (' . $this->mServer . ')';
 914                 }
 915                 return $error;
 916         }
 917         /**
 918          * Get the number of rows affected by the last write query
 919          * See mysql_affected_rows() for more details
 920          */
 921         function affectedRows() { return mysql_affected_rows( $this->mConn ); }
 922         /**#@-*/ // end of template : @param $result
 923
 924         /**
 925          * Simple UPDATE wrapper
 926          * Usually aborts on failure
 927          * If errors are explicitly ignored, returns success
 928          *
 929          * This function exists for historical reasons, Database::update() has a more standard
 930          * calling convention and feature set
 931          */
 932         function set( $table, $var, $value, $cond, $fname = 'Database::set' )
 933         {
 934                 $table = $this->tableName( $table );
 935                 $sql = "UPDATE $table SET $var = '" .
 936                   $this->strencode( $value ) . "' WHERE ($cond)";
 937                 return (bool)$this->query( $sql, $fname );
 938         }
 939
 940         /**
 941          * Simple SELECT wrapper, returns a single field, input must be encoded
 942          * Usually aborts on failure
 943          * If errors are explicitly ignored, returns FALSE on failure
 944          */
 945         function selectField( $table, $var, $cond='', $fname = 'Database::selectField', $options = array() ) {
 946                 if ( !is_array( $options ) ) {
 947                         $options = array( $options );
 948                 }
 949                 $options['LIMIT'] = 1;
 950
 951                 $res = $this->select( $table, $var, $cond, $fname, $options );
 952                 if ( $res === false || !$this->numRows( $res ) ) {
 953                         return false;
 954                 }
 955                 $row = $this->fetchRow( $res );
 956                 if ( $row !== false ) {
 957                         $this->freeResult( $res );
 958                         return $row[0];
 959                 } else {
 960                         return false;
 961                 }
 962         }
 963
 964         /**
 965          * Returns an optional USE INDEX clause to go after the table, and a
 966          * string to go at the end of the query
 967          *
 968          * @private
 969          *
 970          * @param array $options an associative array of options to be turned into
 971          *              an SQL query, valid keys are listed in the function.
 972          * @return array
 973          */
 974         function makeSelectOptions( $options ) {
 975                 $tailOpts = '';
 976                 $startOpts = '';
 977
 978                 $noKeyOptions = array();
 979                 foreach ( $options as $key => $option ) {
 980                         if ( is_numeric( $key ) ) {
 981                                 $noKeyOptions[$option] = true;
 982                         }
 983                 }
 984
 985                 if ( isset( $options['GROUP BY'] ) ) $tailOpts .= " GROUP BY {$options['GROUP BY']}";
 986                 if ( isset( $options['ORDER BY'] ) ) $tailOpts .= " ORDER BY {$options['ORDER BY']}";
 987
 988                 if (isset($options['LIMIT'])) {
 989                         $tailOpts .= $this->limitResult('', $options['LIMIT'],
 990                                 isset($options['OFFSET']) ? $options['OFFSET'] : false);
 991                 }
 992
 993                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) $tailOpts .= ' FOR UPDATE';
 994                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) $tailOpts .= ' LOCK IN SHARE MODE';
 995                 if ( isset( $noKeyOptions['DISTINCT'] ) && isset( $noKeyOptions['DISTINCTROW'] ) ) $startOpts .= 'DISTINCT';
 996
 997                 # Various MySQL extensions
 998                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) $startOpts .= ' /*! STRAIGHT_JOIN */';
 999                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) $startOpts .= ' HIGH_PRIORITY';
1000                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) $startOpts .= ' SQL_BIG_RESULT';
1001                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) $startOpts .= ' SQL_BUFFER_RESULT';
1002                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) $startOpts .= ' SQL_SMALL_RESULT';
1003                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) $startOpts .= ' SQL_CALC_FOUND_ROWS';
1004                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) $startOpts .= ' SQL_CACHE';
1005                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) $startOpts .= ' SQL_NO_CACHE';
1006
1007                 if ( isset( $options['USE INDEX'] ) && ! is_array( $options['USE INDEX'] ) ) {
1008                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
1009                 } else {
1010                         $useIndex = '';
1011                 }
1012
1013                 return array( $startOpts, $useIndex, $tailOpts );
1014         }
1015
1016         /**
1017          * SELECT wrapper
1018          *
1019          * @param mixed  $table   Array or string, table name(s) (prefix auto-added)
1020          * @param mixed  $vars    Array or string, field name(s) to be retrieved
1021          * @param mixed  $conds   Array or string, condition(s) for WHERE
1022          * @param string $fname   Calling function name (use __METHOD__) for logs/profiling
1023          * @param array  $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
1024          *                        see Database::makeSelectOptions code for list of supported stuff
1025          * @return mixed Database result resource (feed to Database::fetchObject or whatever), or false on failure
1026          */
1027         function select( $table, $vars, $conds='', $fname = 'Database::select', $options = array() )
1028         {
1029                 if( is_array( $vars ) ) {
1030                         $vars = implode( ',', $vars );
1031                 }
1032                 if( !is_array( $options ) ) {
1033                         $options = array( $options );
1034                 }
1035                 if( is_array( $table ) ) {
1036                         if ( isset( $options['USE INDEX'] ) && is_array( $options['USE INDEX'] ) )
1037                                 $from = ' FROM ' . $this->tableNamesWithUseIndex( $table, $options['USE INDEX'] );
1038                         else
1039                                 $from = ' FROM ' . implode( ',', array_map( array( &$this, 'tableName' ), $table ) );
1040                 } elseif ($table!='') {
1041                         $from = ' FROM ' . $this->tableName( $table );
1042                 } else {
1043                         $from = '';
1044                 }
1045
1046                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $options );
1047
1048                 if( !empty( $conds ) ) {
1049                         if ( is_array( $conds ) ) {
1050                                 $conds = $this->makeList( $conds, LIST_AND );
1051                         }
1052                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $tailOpts";
1053                 } else {
1054                         $sql = "SELECT $startOpts $vars $from $useIndex $tailOpts";
1055                 }
1056
1057                 return $this->query( $sql, $fname );
1058         }
1059
1060         /**
1061          * Single row SELECT wrapper
1062          * Aborts or returns FALSE on error
1063          *
1064          * $vars: the selected variables
1065          * $conds: a condition map, terms are ANDed together.
1066          *   Items with numeric keys are taken to be literal conditions
1067          * Takes an array of selected variables, and a condition map, which is ANDed
1068          * e.g: selectRow( "page", array( "page_id" ), array( "page_namespace" =>
1069          * NS_MAIN, "page_title" => "Astronomy" ) )   would return an object where
1070          * $obj- >page_id is the ID of the Astronomy article
1071          *
1072          * @todo migrate documentation to phpdocumentor format
1073          */
1074         function selectRow( $table, $vars, $conds, $fname = 'Database::selectRow', $options = array() ) {
1075                 $options['LIMIT'] = 1;
1076                 $res = $this->select( $table, $vars, $conds, $fname, $options );
1077                 if ( $res === false )
1078                         return false;
1079                 if ( !$this->numRows($res) ) {
1080                         $this->freeResult($res);
1081                         return false;
1082                 }
1083                 $obj = $this->fetchObject( $res );
1084                 $this->freeResult( $res );
1085                 return $obj;
1086
1087         }
1088
1089         /**
1090          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1091          * It's only slightly flawed. Don't use for anything important.
1092          *
1093          * @param string $sql A SQL Query
1094          * @static
1095          */
1096         static function generalizeSQL( $sql ) {
1097                 # This does the same as the regexp below would do, but in such a way
1098                 # as to avoid crashing php on some large strings.
1099                 # $sql = preg_replace ( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql);
1100
1101                 $sql = str_replace ( "\\\\", '', $sql);
1102                 $sql = str_replace ( "\\'", '', $sql);
1103                 $sql = str_replace ( "\\\"", '', $sql);
1104                 $sql = preg_replace ("/'.*'/s", "'X'", $sql);
1105                 $sql = preg_replace ('/".*"/s', "'X'", $sql);
1106
1107                 # All newlines, tabs, etc replaced by single space
1108                 $sql = preg_replace ( '/\s+/', ' ', $sql);
1109
1110                 # All numbers => N
1111                 $sql = preg_replace ('/-?[0-9]+/s', 'N', $sql);
1112
1113                 return $sql;
1114         }
1115
1116         /**
1117          * Determines whether a field exists in a table
1118          * Usually aborts on failure
1119          * If errors are explicitly ignored, returns NULL on failure
1120          */
1121         function fieldExists( $table, $field, $fname = 'Database::fieldExists' ) {
1122                 $table = $this->tableName( $table );
1123                 $res = $this->query( 'DESCRIBE '.$table, $fname );
1124                 if ( !$res ) {
1125                         return NULL;
1126                 }
1127
1128                 $found = false;
1129
1130                 while ( $row = $this->fetchObject( $res ) ) {
1131                         if ( $row->Field == $field ) {
1132                                 $found = true;
1133                                 break;
1134                         }
1135                 }
1136                 return $found;
1137         }
1138
1139         /**
1140          * Determines whether an index exists
1141          * Usually aborts on failure
1142          * If errors are explicitly ignored, returns NULL on failure
1143          */
1144         function indexExists( $table, $index, $fname = 'Database::indexExists' ) {
1145                 $info = $this->indexInfo( $table, $index, $fname );
1146                 if ( is_null( $info ) ) {
1147                         return NULL;
1148                 } else {
1149                         return $info !== false;
1150                 }
1151         }
1152
1153
1154         /**
1155          * Get information about an index into an object
1156          * Returns false if the index does not exist
1157          */
1158         function indexInfo( $table, $index, $fname = 'Database::indexInfo' ) {
1159                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
1160                 # SHOW INDEX should work for 3.x and up:
1161                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
1162                 $table = $this->tableName( $table );
1163                 $sql = 'SHOW INDEX FROM '.$table;
1164                 $res = $this->query( $sql, $fname );
1165                 if ( !$res ) {
1166                         return NULL;
1167                 }
1168
1169                 $result = array();
1170                 while ( $row = $this->fetchObject( $res ) ) {
1171                         if ( $row->Key_name == $index ) {
1172                                 $result[] = $row;
1173                         }
1174                 }
1175                 $this->freeResult($res);
1176
1177                 return empty($result) ? false : $result;
1178         }
1179
1180         /**
1181          * Query whether a given table exists
1182          */
1183         function tableExists( $table ) {
1184                 $table = $this->tableName( $table );
1185                 $old = $this->ignoreErrors( true );
1186                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1" );
1187                 $this->ignoreErrors( $old );
1188                 if( $res ) {
1189                         $this->freeResult( $res );
1190                         return true;
1191                 } else {
1192                         return false;
1193                 }
1194         }
1195
1196         /**
1197          * mysql_fetch_field() wrapper
1198          * Returns false if the field doesn't exist
1199          *
1200          * @param $table
1201          * @param $field
1202          */
1203         function fieldInfo( $table, $field ) {
1204                 $table = $this->tableName( $table );
1205                 $res = $this->query( "SELECT * FROM $table LIMIT 1" );
1206                 $n = mysql_num_fields( $res );
1207                 for( $i = 0; $i < $n; $i++ ) {
1208                         $meta = mysql_fetch_field( $res, $i );
1209                         if( $field == $meta->name ) {
1210                                 return $meta;
1211                         }
1212                 }
1213                 return false;
1214         }
1215
1216         /**
1217          * mysql_field_type() wrapper
1218          */
1219         function fieldType( $res, $index ) {
1220                 return mysql_field_type( $res, $index );
1221         }
1222
1223         /**
1224          * Determines if a given index is unique
1225          */
1226         function indexUnique( $table, $index ) {
1227                 $indexInfo = $this->indexInfo( $table, $index );
1228                 if ( !$indexInfo ) {
1229                         return NULL;
1230                 }
1231                 return !$indexInfo[0]->Non_unique;
1232         }
1233
1234         /**
1235          * INSERT wrapper, inserts an array into a table
1236          *
1237          * $a may be a single associative array, or an array of these with numeric keys, for
1238          * multi-row insert.
1239          *
1240          * Usually aborts on failure
1241          * If errors are explicitly ignored, returns success
1242          */
1243         function insert( $table, $a, $fname = 'Database::insert', $options = array() ) {
1244                 # No rows to insert, easy just return now
1245                 if ( !count( $a ) ) {
1246                         return true;
1247                 }
1248
1249                 $table = $this->tableName( $table );
1250                 if ( !is_array( $options ) ) {
1251                         $options = array( $options );
1252                 }
1253                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1254                         $multi = true;
1255                         $keys = array_keys( $a[0] );
1256                 } else {
1257                         $multi = false;
1258                         $keys = array_keys( $a );
1259                 }
1260
1261                 $sql = 'INSERT ' . implode( ' ', $options ) .
1262                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1263
1264                 if ( $multi ) {
1265                         $first = true;
1266                         foreach ( $a as $row ) {
1267                                 if ( $first ) {
1268                                         $first = false;
1269                                 } else {
1270                                         $sql .= ',';
1271                                 }
1272                                 $sql .= '(' . $this->makeList( $row ) . ')';
1273                         }
1274                 } else {
1275                         $sql .= '(' . $this->makeList( $a ) . ')';
1276                 }
1277                 return (bool)$this->query( $sql, $fname );
1278         }
1279
1280         /**
1281          * Make UPDATE options for the Database::update function
1282          *
1283          * @private
1284          * @param array $options The options passed to Database::update
1285          * @return string
1286          */
1287         function makeUpdateOptions( $options ) {
1288                 if( !is_array( $options ) ) {
1289                         $options = array( $options );
1290                 }
1291                 $opts = array();
1292                 if ( in_array( 'LOW_PRIORITY', $options ) )
1293                         $opts[] = $this->lowPriorityOption();
1294                 if ( in_array( 'IGNORE', $options ) )
1295                         $opts[] = 'IGNORE';
1296                 return implode(' ', $opts);
1297         }
1298
1299         /**
1300          * UPDATE wrapper, takes a condition array and a SET array
1301          *
1302          * @param string $table  The table to UPDATE
1303          * @param array  $values An array of values to SET
1304          * @param array  $conds  An array of conditions (WHERE). Use '*' to update all rows.
1305          * @param string $fname  The Class::Function calling this function
1306          *                       (for the log)
1307          * @param array  $options An array of UPDATE options, can be one or
1308          *                        more of IGNORE, LOW_PRIORITY
1309          */
1310         function update( $table, $values, $conds, $fname = 'Database::update', $options = array() ) {
1311                 $table = $this->tableName( $table );
1312                 $opts = $this->makeUpdateOptions( $options );
1313                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1314                 if ( $conds != '*' ) {
1315                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1316                 }
1317                 $this->query( $sql, $fname );
1318         }
1319
1320         /**
1321          * Makes an encoded list of strings from an array
1322          * $mode:
1323          *        LIST_COMMA         - comma separated, no field names
1324          *        LIST_AND           - ANDed WHERE clause (without the WHERE)
1325          *        LIST_OR            - ORed WHERE clause (without the WHERE)
1326          *        LIST_SET           - comma separated with field names, like a SET clause
1327          *        LIST_NAMES         - comma separated field names
1328          */
1329         function makeList( $a, $mode = LIST_COMMA ) {
1330                 if ( !is_array( $a ) ) {
1331                         throw new DBUnexpectedError( $this, 'Database::makeList called with incorrect parameters' );
1332                 }
1333
1334                 $first = true;
1335                 $list = '';
1336                 foreach ( $a as $field => $value ) {
1337                         if ( !$first ) {
1338                                 if ( $mode == LIST_AND ) {
1339                                         $list .= ' AND ';
1340                                 } elseif($mode == LIST_OR) {
1341                                         $list .= ' OR ';
1342                                 } else {
1343                                         $list .= ',';
1344                                 }
1345                         } else {
1346                                 $first = false;
1347                         }
1348                         if ( ($mode == LIST_AND || $mode == LIST_OR) && is_numeric( $field ) ) {
1349                                 $list .= "($value)";
1350                         } elseif ( ($mode == LIST_SET) && is_numeric( $field ) ) {
1351                                 $list .= "$value";
1352                         } elseif ( ($mode == LIST_AND || $mode == LIST_OR) && is_array ($value) ) {
1353                                 $list .= $field." IN (".$this->makeList($value).") ";
1354                         } else {
1355                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1356                                         $list .= "$field = ";
1357                                 }
1358                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1359                         }
1360                 }
1361                 return $list;
1362         }
1363
1364         /**
1365          * Change the current database
1366          */
1367         function selectDB( $db ) {
1368                 $this->mDBname = $db;
1369                 return mysql_select_db( $db, $this->mConn );
1370         }
1371
1372         /**
1373          * Format a table name ready for use in constructing an SQL query
1374          *
1375          * This does two important things: it quotes table names which as necessary,
1376          * and it adds a table prefix if there is one.
1377          *
1378          * All functions of this object which require a table name call this function
1379          * themselves. Pass the canonical name to such functions. This is only needed
1380          * when calling query() directly.
1381          *
1382          * @param string $name database table name
1383          */
1384         function tableName( $name ) {
1385                 global $wgSharedDB;
1386                 # Skip quoted literals
1387                 if ( $name{0} != '`' ) {
1388                         if ( $this->mTablePrefix !== '' &&  strpos( '.', $name ) === false ) {
1389                                 $name = "{$this->mTablePrefix}$name";
1390                         }
1391                         if ( isset( $wgSharedDB ) && "{$this->mTablePrefix}user" == $name ) {
1392                                 $name = "`$wgSharedDB`.`$name`";
1393                         } else {
1394                                 # Standard quoting
1395                                 $name = "`$name`";
1396                         }
1397                 }
1398                 return $name;
1399         }
1400
1401         /**
1402          * Fetch a number of table names into an array
1403          * This is handy when you need to construct SQL for joins
1404          *
1405          * Example:
1406          * extract($dbr->tableNames('user','watchlist'));
1407          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1408          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1409          */
1410         public function tableNames() {
1411                 $inArray = func_get_args();
1412                 $retVal = array();
1413                 foreach ( $inArray as $name ) {
1414                         $retVal[$name] = $this->tableName( $name );
1415                 }
1416                 return $retVal;
1417         }
1418
1419         /**
1420          * @desc: Fetch a number of table names into an zero-indexed numerical array
1421          * This is handy when you need to construct SQL for joins
1422          *
1423          * Example:
1424          * list( $user, $watchlist ) = $dbr->tableNames('user','watchlist');
1425          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1426          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1427          */
1428         public function tableNamesN() {
1429                 $inArray = func_get_args();
1430                 $retVal = array();
1431                 foreach ( $inArray as $name ) {
1432                         $retVal[] = $this->tableName( $name );
1433                 }
1434                 return $retVal;
1435         }
1436
1437         /**
1438          * @private
1439          */
1440         function tableNamesWithUseIndex( $tables, $use_index ) {
1441                 $ret = array();
1442
1443                 foreach ( $tables as $table )
1444                         if ( @$use_index[$table] !== null )
1445                                 $ret[] = $this->tableName( $table ) . ' ' . $this->useIndexClause( implode( ',', (array)$use_index[$table] ) );
1446                         else
1447                                 $ret[] = $this->tableName( $table );
1448
1449                 return implode( ',', $ret );
1450         }
1451
1452         /**
1453          * Wrapper for addslashes()
1454          * @param string $s String to be slashed.
1455          * @return string slashed string.
1456          */
1457         function strencode( $s ) {
1458                 return mysql_real_escape_string( $s, $this->mConn );
1459         }
1460
1461         /**
1462          * If it's a string, adds quotes and backslashes
1463          * Otherwise returns as-is
1464          */
1465         function addQuotes( $s ) {
1466                 if ( is_null( $s ) ) {
1467                         return 'NULL';
1468                 } else {
1469                         # This will also quote numeric values. This should be harmless,
1470                         # and protects against weird problems that occur when they really
1471                         # _are_ strings such as article titles and string->number->string
1472                         # conversion is not 1:1.
1473                         return "'" . $this->strencode( $s ) . "'";
1474                 }
1475         }
1476
1477         /**
1478          * Escape string for safe LIKE usage
1479          */
1480         function escapeLike( $s ) {
1481                 $s=$this->strencode( $s );
1482                 $s=str_replace(array('%','_'),array('\%','\_'),$s);
1483                 return $s;
1484         }
1485
1486         /**
1487          * Returns an appropriately quoted sequence value for inserting a new row.
1488          * MySQL has autoincrement fields, so this is just NULL. But the PostgreSQL
1489          * subclass will return an integer, and save the value for insertId()
1490          */
1491         function nextSequenceValue( $seqName ) {
1492                 return NULL;
1493         }
1494
1495         /**
1496          * USE INDEX clause
1497          * PostgreSQL doesn't have them and returns ""
1498          */
1499         function useIndexClause( $index ) {
1500                 return "FORCE INDEX ($index)";
1501         }
1502
1503         /**
1504          * REPLACE query wrapper
1505          * PostgreSQL simulates this with a DELETE followed by INSERT
1506          * $row is the row to insert, an associative array
1507          * $uniqueIndexes is an array of indexes. Each element may be either a
1508          * field name or an array of field names
1509          *
1510          * It may be more efficient to leave off unique indexes which are unlikely to collide.
1511          * However if you do this, you run the risk of encountering errors which wouldn't have
1512          * occurred in MySQL
1513          *
1514          * @todo migrate comment to phodocumentor format
1515          */
1516         function replace( $table, $uniqueIndexes, $rows, $fname = 'Database::replace' ) {
1517                 $table = $this->tableName( $table );
1518
1519                 # Single row case
1520                 if ( !is_array( reset( $rows ) ) ) {
1521                         $rows = array( $rows );
1522                 }
1523
1524                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) .') VALUES ';
1525                 $first = true;
1526                 foreach ( $rows as $row ) {
1527                         if ( $first ) {
1528                                 $first = false;
1529                         } else {
1530                                 $sql .= ',';
1531                         }
1532                         $sql .= '(' . $this->makeList( $row ) . ')';
1533                 }
1534                 return $this->query( $sql, $fname );
1535         }
1536
1537         /**
1538          * DELETE where the condition is a join
1539          * MySQL does this with a multi-table DELETE syntax, PostgreSQL does it with sub-selects
1540          *
1541          * For safety, an empty $conds will not delete everything. If you want to delete all rows where the
1542          * join condition matches, set $conds='*'
1543          *
1544          * DO NOT put the join condition in $conds
1545          *
1546          * @param string $delTable The table to delete from.
1547          * @param string $joinTable The other table.
1548          * @param string $delVar The variable to join on, in the first table.
1549          * @param string $joinVar The variable to join on, in the second table.
1550          * @param array $conds Condition array of field names mapped to variables, ANDed together in the WHERE clause
1551          */
1552         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'Database::deleteJoin' ) {
1553                 if ( !$conds ) {
1554                         throw new DBUnexpectedError( $this, 'Database::deleteJoin() called with empty $conds' );
1555                 }
1556
1557                 $delTable = $this->tableName( $delTable );
1558                 $joinTable = $this->tableName( $joinTable );
1559                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1560                 if ( $conds != '*' ) {
1561                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1562                 }
1563
1564                 return $this->query( $sql, $fname );
1565         }
1566
1567         /**
1568          * Returns the size of a text field, or -1 for "unlimited"
1569          */
1570         function textFieldSize( $table, $field ) {
1571                 $table = $this->tableName( $table );
1572                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
1573                 $res = $this->query( $sql, 'Database::textFieldSize' );
1574                 $row = $this->fetchObject( $res );
1575                 $this->freeResult( $res );
1576
1577                 $m = array();
1578                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
1579                         $size = $m[1];
1580                 } else {
1581                         $size = -1;
1582                 }
1583                 return $size;
1584         }
1585
1586         /**
1587          * @return string Returns the text of the low priority option if it is supported, or a blank string otherwise
1588          */
1589         function lowPriorityOption() {
1590                 return 'LOW_PRIORITY';
1591         }
1592
1593         /**
1594          * DELETE query wrapper
1595          *
1596          * Use $conds == "*" to delete all rows
1597          */
1598         function delete( $table, $conds, $fname = 'Database::delete' ) {
1599                 if ( !$conds ) {
1600                         throw new DBUnexpectedError( $this, 'Database::delete() called with no conditions' );
1601                 }
1602                 $table = $this->tableName( $table );
1603                 $sql = "DELETE FROM $table";
1604                 if ( $conds != '*' ) {
1605                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1606                 }
1607                 return $this->query( $sql, $fname );
1608         }
1609
1610         /**
1611          * INSERT SELECT wrapper
1612          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
1613          * Source items may be literals rather than field names, but strings should be quoted with Database::addQuotes()
1614          * $conds may be "*" to copy the whole table
1615          * srcTable may be an array of tables.
1616          */
1617         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'Database::insertSelect',
1618                 $insertOptions = array(), $selectOptions = array() )
1619         {
1620                 $destTable = $this->tableName( $destTable );
1621                 if ( is_array( $insertOptions ) ) {
1622                         $insertOptions = implode( ' ', $insertOptions );
1623                 }
1624                 if( !is_array( $selectOptions ) ) {
1625                         $selectOptions = array( $selectOptions );
1626                 }
1627                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1628                 if( is_array( $srcTable ) ) {
1629                         $srcTable =  implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1630                 } else {
1631                         $srcTable = $this->tableName( $srcTable );
1632                 }
1633                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1634                         " SELECT $startOpts " . implode( ',', $varMap ) .
1635                         " FROM $srcTable $useIndex ";
1636                 if ( $conds != '*' ) {
1637                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1638                 }
1639                 $sql .= " $tailOpts";
1640                 return $this->query( $sql, $fname );
1641         }
1642
1643         /**
1644          * Construct a LIMIT query with optional offset
1645          * This is used for query pages
1646          * $sql string SQL query we will append the limit too
1647          * $limit integer the SQL limit
1648          * $offset integer the SQL offset (default false)
1649          */
1650         function limitResult($sql, $limit, $offset=false) {
1651                 if( !is_numeric($limit) ) {
1652                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
1653                 }
1654                 return " $sql LIMIT "
1655                                 . ( (is_numeric($offset) && $offset != 0) ? "{$offset}," : "" )
1656                                 . "{$limit} ";
1657         }
1658         function limitResultForUpdate($sql, $num) {
1659                 return $this->limitResult($sql, $num, 0);
1660         }
1661
1662         /**
1663          * Returns an SQL expression for a simple conditional.
1664          * Uses IF on MySQL.
1665          *
1666          * @param string $cond SQL expression which will result in a boolean value
1667          * @param string $trueVal SQL expression to return if true
1668          * @param string $falseVal SQL expression to return if false
1669          * @return string SQL fragment
1670          */
1671         function conditional( $cond, $trueVal, $falseVal ) {
1672                 return " IF($cond, $trueVal, $falseVal) ";
1673         }
1674
1675         /**
1676          * Determines if the last failure was due to a deadlock
1677          */
1678         function wasDeadlock() {
1679                 return $this->lastErrno() == 1213;
1680         }
1681
1682         /**
1683          * Perform a deadlock-prone transaction.
1684          *
1685          * This function invokes a callback function to perform a set of write
1686          * queries. If a deadlock occurs during the processing, the transaction
1687          * will be rolled back and the callback function will be called again.
1688          *
1689          * Usage:
1690          *   $dbw->deadlockLoop( callback, ... );
1691          *
1692          * Extra arguments are passed through to the specified callback function.
1693          *
1694          * Returns whatever the callback function returned on its successful,
1695          * iteration, or false on error, for example if the retry limit was
1696          * reached.
1697          */
1698         function deadlockLoop() {
1699                 $myFname = 'Database::deadlockLoop';
1700
1701                 $this->begin();
1702                 $args = func_get_args();
1703                 $function = array_shift( $args );
1704                 $oldIgnore = $this->ignoreErrors( true );
1705                 $tries = DEADLOCK_TRIES;
1706                 if ( is_array( $function ) ) {
1707                         $fname = $function[0];
1708                 } else {
1709                         $fname = $function;
1710                 }
1711                 do {
1712                         $retVal = call_user_func_array( $function, $args );
1713                         $error = $this->lastError();
1714                         $errno = $this->lastErrno();
1715                         $sql = $this->lastQuery();
1716
1717                         if ( $errno ) {
1718                                 if ( $this->wasDeadlock() ) {
1719                                         # Retry
1720                                         usleep( mt_rand( DEADLOCK_DELAY_MIN, DEADLOCK_DELAY_MAX ) );
1721                                 } else {
1722                                         $this->reportQueryError( $error, $errno, $sql, $fname );
1723                                 }
1724                         }
1725                 } while( $this->wasDeadlock() && --$tries > 0 );
1726                 $this->ignoreErrors( $oldIgnore );
1727                 if ( $tries <= 0 ) {
1728                         $this->query( 'ROLLBACK', $myFname );
1729                         $this->reportQueryError( $error, $errno, $sql, $fname );
1730                         return false;
1731                 } else {
1732                         $this->query( 'COMMIT', $myFname );
1733                         return $retVal;
1734                 }
1735         }
1736
1737         /**
1738          * Do a SELECT MASTER_POS_WAIT()
1739          *
1740          * @param string $file the binlog file
1741          * @param string $pos the binlog position
1742          * @param integer $timeout the maximum number of seconds to wait for synchronisation
1743          */
1744         function masterPosWait( $file, $pos, $timeout ) {
1745                 $fname = 'Database::masterPosWait';
1746                 wfProfileIn( $fname );
1747
1748
1749                 # Commit any open transactions
1750                 $this->immediateCommit();
1751
1752                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
1753                 $encFile = $this->strencode( $file );
1754                 $sql = "SELECT MASTER_POS_WAIT('$encFile', $pos, $timeout)";
1755                 $res = $this->doQuery( $sql );
1756                 if ( $res && $row = $this->fetchRow( $res ) ) {
1757                         $this->freeResult( $res );
1758                         wfProfileOut( $fname );
1759                         return $row[0];
1760                 } else {
1761                         wfProfileOut( $fname );
1762                         return false;
1763                 }
1764         }
1765
1766         /**
1767          * Get the position of the master from SHOW SLAVE STATUS
1768          */
1769         function getSlavePos() {
1770                 $res = $this->query( 'SHOW SLAVE STATUS', 'Database::getSlavePos' );
1771                 $row = $this->fetchObject( $res );
1772                 if ( $row ) {
1773                         return array( $row->Master_Log_File, $row->Read_Master_Log_Pos );
1774                 } else {
1775                         return array( false, false );
1776                 }
1777         }
1778
1779         /**
1780          * Get the position of the master from SHOW MASTER STATUS
1781          */
1782         function getMasterPos() {
1783                 $res = $this->query( 'SHOW MASTER STATUS', 'Database::getMasterPos' );
1784                 $row = $this->fetchObject( $res );
1785                 if ( $row ) {
1786                         return array( $row->File, $row->Position );
1787                 } else {
1788                         return array( false, false );
1789                 }
1790         }
1791
1792         /**
1793          * Begin a transaction, committing any previously open transaction
1794          */
1795         function begin( $fname = 'Database::begin' ) {
1796                 $this->query( 'BEGIN', $fname );
1797                 $this->mTrxLevel = 1;
1798         }
1799
1800         /**
1801          * End a transaction
1802          */
1803         function commit( $fname = 'Database::commit' ) {
1804                 $this->query( 'COMMIT', $fname );
1805                 $this->mTrxLevel = 0;
1806         }
1807
1808         /**
1809          * Rollback a transaction
1810          */
1811         function rollback( $fname = 'Database::rollback' ) {
1812                 $this->query( 'ROLLBACK', $fname );
1813                 $this->mTrxLevel = 0;
1814         }
1815
1816         /**
1817          * Begin a transaction, committing any previously open transaction
1818          * @deprecated use begin()
1819          */
1820         function immediateBegin( $fname = 'Database::immediateBegin' ) {
1821                 $this->begin();
1822         }
1823
1824         /**
1825          * Commit transaction, if one is open
1826          * @deprecated use commit()
1827          */
1828         function immediateCommit( $fname = 'Database::immediateCommit' ) {
1829                 $this->commit();
1830         }
1831
1832         /**
1833          * Return MW-style timestamp used for MySQL schema
1834          */
1835         function timestamp( $ts=0 ) {
1836                 return wfTimestamp(TS_MW,$ts);
1837         }
1838
1839         /**
1840          * Local database timestamp format or null
1841          */
1842         function timestampOrNull( $ts = null ) {
1843                 if( is_null( $ts ) ) {
1844                         return null;
1845                 } else {
1846                         return $this->timestamp( $ts );
1847                 }
1848         }
1849
1850         /**
1851          * @todo document
1852          */
1853         function resultObject( $result ) {
1854                 if( empty( $result ) ) {
1855                         return NULL;
1856                 } else {
1857                         return new ResultWrapper( $this, $result );
1858                 }
1859         }
1860
1861         /**
1862          * Return aggregated value alias
1863          */
1864         function aggregateValue ($valuedata,$valuename='value') {
1865                 return $valuename;
1866         }
1867
1868         /**
1869          * @return string wikitext of a link to the server software's web site
1870          */
1871         function getSoftwareLink() {
1872                 return "[http://www.mysql.com/ MySQL]";
1873         }
1874
1875         /**
1876          * @return string Version information from the database
1877          */
1878         function getServerVersion() {
1879                 return mysql_get_server_info( $this->mConn );
1880         }
1881
1882         /**
1883          * Ping the server and try to reconnect if it there is no connection
1884          */
1885         function ping() {
1886                 if( function_exists( 'mysql_ping' ) ) {
1887                         return mysql_ping( $this->mConn );
1888                 } else {
1889                         wfDebug( "Tried to call mysql_ping but this is ancient PHP version. Faking it!\n" );
1890                         return true;
1891                 }
1892         }
1893
1894         /**
1895          * Get slave lag.
1896          * At the moment, this will only work if the DB user has the PROCESS privilege
1897          */
1898         function getLag() {
1899                 $res = $this->query( 'SHOW PROCESSLIST' );
1900                 # Find slave SQL thread. Assumed to be the second one running, which is a bit
1901                 # dubious, but unfortunately there's no easy rigorous way
1902                 while ( $row = $this->fetchObject( $res ) ) {
1903                         /* This should work for most situations - when default db
1904                          * for thread is not specified, it had no events executed,
1905                          * and therefore it doesn't know yet how lagged it is.
1906                          *
1907                          * Relay log I/O thread does not select databases.
1908                          */
1909                         if ( $row->User == 'system user' &&
1910                                 $row->State != 'Waiting for master to send event' &&
1911                                 $row->State != 'Connecting to master' &&
1912                                 $row->State != 'Queueing master event to the relay log' &&
1913                                 $row->State != 'Waiting for master update' &&
1914                                 $row->State != 'Requesting binlog dump'
1915                                 ) {
1916                                 # This is it, return the time (except -ve)
1917                                 if ( $row->Time > 0x7fffffff ) {
1918                                         return false;
1919                                 } else {
1920                                         return $row->Time;
1921                                 }
1922                         }
1923                 }
1924                 return false;
1925         }
1926
1927         /**
1928          * Get status information from SHOW STATUS in an associative array
1929          */
1930         function getStatus($which="%") {
1931                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1932                 $status = array();
1933                 while ( $row = $this->fetchObject( $res ) ) {
1934                         $status[$row->Variable_name] = $row->Value;
1935                 }
1936                 return $status;
1937         }
1938
1939         /**
1940          * Return the maximum number of items allowed in a list, or 0 for unlimited.
1941          */
1942         function maxListLen() {
1943                 return 0;
1944         }
1945
1946         function encodeBlob($b) {
1947                 return $b;
1948         }
1949
1950         function decodeBlob($b) {
1951                 return $b;
1952         }
1953
1954         /**
1955          * Read and execute SQL commands from a file.
1956          * Returns true on success, error string on failure
1957          */
1958         function sourceFile( $filename ) {
1959                 $fp = fopen( $filename, 'r' );
1960                 if ( false === $fp ) {
1961                         return "Could not open \"{$filename}\".\n";
1962                 }
1963
1964                 $cmd = "";
1965                 $done = false;
1966                 $dollarquote = false;
1967
1968                 while ( ! feof( $fp ) ) {
1969                         $line = trim( fgets( $fp, 1024 ) );
1970                         $sl = strlen( $line ) - 1;
1971
1972                         if ( $sl < 0 ) { continue; }
1973                         if ( '-' == $line{0} && '-' == $line{1} ) { continue; }
1974
1975                         ## Allow dollar quoting for function declarations
1976                         if (substr($line,0,4) == '$mw$') {
1977                                 if ($dollarquote) {
1978                                         $dollarquote = false;
1979                                         $done = true;
1980                                 }
1981                                 else {
1982                                         $dollarquote = true;
1983                                 }
1984                         }
1985                         else if (!$dollarquote) {
1986                                 if ( ';' == $line{$sl} && ($sl < 2 || ';' != $line{$sl - 1})) {
1987                                         $done = true;
1988                                         $line = substr( $line, 0, $sl );
1989                                 }
1990                         }
1991
1992                         if ( '' != $cmd ) { $cmd .= ' '; }
1993                         $cmd .= "$line\n";
1994
1995                         if ( $done ) {
1996                                 $cmd = str_replace(';;', ";", $cmd);
1997                                 $cmd = $this->replaceVars( $cmd );
1998                                 $res = $this->query( $cmd, 'dbsource', true );
1999
2000                                 if ( false === $res ) {
2001                                         $err = $this->lastError();
2002                                         return "Query \"{$cmd}\" failed with error code \"$err\".\n";
2003                                 }
2004
2005                                 $cmd = '';
2006                                 $done = false;
2007                         }
2008                 }
2009                 fclose( $fp );
2010                 return true;
2011         }
2012
2013         /**
2014          * Replace variables in sourced SQL
2015          */
2016         protected function replaceVars( $ins ) {
2017                 $varnames = array(
2018                         'wgDBserver', 'wgDBname', 'wgDBintlname', 'wgDBuser',
2019                         'wgDBpassword', 'wgDBsqluser', 'wgDBsqlpassword',
2020                         'wgDBadminuser', 'wgDBadminpassword',
2021                 );
2022
2023                 // Ordinary variables
2024                 foreach ( $varnames as $var ) {
2025                         if( isset( $GLOBALS[$var] ) ) {
2026                                 $val = addslashes( $GLOBALS[$var] ); // FIXME: safety check?
2027                                 $ins = str_replace( '{$' . $var . '}', $val, $ins );
2028                                 $ins = str_replace( '/*$' . $var . '*/`', '`' . $val, $ins );
2029                                 $ins = str_replace( '/*$' . $var . '*/', $val, $ins );
2030                         }
2031                 }
2032
2033                 // Table prefixes
2034                 $ins = preg_replace_callback( '/\/\*(?:\$wgDBprefix|_)\*\/([a-z_]*)/',
2035                         array( &$this, 'tableNameCallback' ), $ins );
2036                 return $ins;
2037         }
2038
2039         /**
2040          * Table name callback
2041          * @private
2042          */
2043         protected function tableNameCallback( $matches ) {
2044                 return $this->tableName( $matches[1] );
2045         }
2046
2047 }
2048
2049 /**
2050  * Database abstraction object for mySQL
2051  * Inherit all methods and properties of Database::Database()
2052  *
2053  * @package MediaWiki
2054  * @see Database
2055  */
2056 class DatabaseMysql extends Database {
2057         # Inherit all
2058 }
2059
2060
2061 /**
2062  * Result wrapper for grabbing data queried by someone else
2063  *
2064  * @package MediaWiki
2065  */
2066 class ResultWrapper {
2067         var $db, $result;
2068
2069         /**
2070          * @todo document
2071          */
2072         function ResultWrapper( &$database, $result ) {
2073                 $this->db =& $database;
2074                 $this->result =& $result;
2075         }
2076
2077         /**
2078          * @todo document
2079          */
2080         function numRows() {
2081                 return $this->db->numRows( $this->result );
2082         }
2083
2084         /**
2085          * @todo document
2086          */
2087         function fetchObject() {
2088                 return $this->db->fetchObject( $this->result );
2089         }
2090
2091         /**
2092          * @todo document
2093          */
2094         function fetchRow() {
2095                 return $this->db->fetchRow( $this->result );
2096         }
2097
2098         /**
2099          * @todo document
2100          */
2101         function free() {
2102                 $this->db->freeResult( $this->result );
2103                 unset( $this->result );
2104                 unset( $this->db );
2105         }
2106
2107         function seek( $row ) {
2108                 $this->db->dataSeek( $this->result, $row );
2109         }
2110
2111 }
2112
2113 ?>