includes/db/DatabaseMssql.php

   1 <?php
   2 /**
   3  * This is the MS SQL Server Native database abstraction layer.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  * @author Joel Penner <a-joelpe at microsoft dot com>
  23  * @author Chris Pucci <a-cpucci at microsoft dot com>
  24  * @author Ryan Biesemeyer <v-ryanbi at microsoft dot com>
  25  * @author Ryan Schmidt <skizzerz at gmail dot com>
  26  */
  27
  28 /**
  29  * @ingroup Database
  30  */
  31 class DatabaseMssql extends DatabaseBase {
  32         protected $mInsertId = null;
  33         protected $mLastResult = null;
  34         protected $mAffectedRows = null;
  35         protected $mSubqueryId = 0;
  36         protected $mScrollableCursor = true;
  37         protected $mPrepareStatements = true;
  38         protected $mBinaryColumnCache = null;
  39         protected $mBitColumnCache = null;
  40         protected $mIgnoreDupKeyErrors = false;
  41         protected $mIgnoreErrors = [];
  42
  43         protected $mPort;
  44
  45         public function cascadingDeletes() {
  46                 return true;
  47         }
  48
  49         public function cleanupTriggers() {
  50                 return false;
  51         }
  52
  53         public function strictIPs() {
  54                 return false;
  55         }
  56
  57         public function implicitGroupby() {
  58                 return false;
  59         }
  60
  61         public function implicitOrderby() {
  62                 return false;
  63         }
  64
  65         public function unionSupportsOrderAndLimit() {
  66                 return false;
  67         }
  68
  69         /**
  70          * Usually aborts on failure
  71          * @param string $server
  72          * @param string $user
  73          * @param string $password
  74          * @param string $dbName
  75          * @throws DBConnectionError
  76          * @return bool|resource|null
  77          */
  78         public function open( $server, $user, $password, $dbName ) {
  79                 # Test for driver support, to avoid suppressed fatal error
  80                 if ( !function_exists( 'sqlsrv_connect' ) ) {
  81                         throw new DBConnectionError(
  82                                 $this,
  83                                 "Microsoft SQL Server Native (sqlsrv) functions missing.
  84                                 You can download the driver from: http://go.microsoft.com/fwlink/?LinkId=123470\n"
  85                         );
  86                 }
  87
  88                 global $wgDBport, $wgDBWindowsAuthentication;
  89
  90                 # e.g. the class is being loaded
  91                 if ( !strlen( $user ) ) {
  92                         return null;
  93                 }
  94
  95                 $this->close();
  96                 $this->mServer = $server;
  97                 $this->mPort = $wgDBport;
  98                 $this->mUser = $user;
  99                 $this->mPassword = $password;
 100                 $this->mDBname = $dbName;
 101
 102                 $connectionInfo = [];
 103
 104                 if ( $dbName ) {
 105                         $connectionInfo['Database'] = $dbName;
 106                 }
 107
 108                 // Decide which auth scenerio to use
 109                 // if we are using Windows auth, don't add credentials to $connectionInfo
 110                 if ( !$wgDBWindowsAuthentication ) {
 111                         $connectionInfo['UID'] = $user;
 112                         $connectionInfo['PWD'] = $password;
 113                 }
 114
 115                 MediaWiki\suppressWarnings();
 116                 $this->mConn = sqlsrv_connect( $server, $connectionInfo );
 117                 MediaWiki\restoreWarnings();
 118
 119                 if ( $this->mConn === false ) {
 120                         throw new DBConnectionError( $this, $this->lastError() );
 121                 }
 122
 123                 $this->mOpened = true;
 124
 125                 return $this->mConn;
 126         }
 127
 128         /**
 129          * Closes a database connection, if it is open
 130          * Returns success, true if already closed
 131          * @return bool
 132          */
 133         protected function closeConnection() {
 134                 return sqlsrv_close( $this->mConn );
 135         }
 136
 137         /**
 138          * @param bool|MssqlResultWrapper|resource $result
 139          * @return bool|MssqlResultWrapper
 140          */
 141         protected function resultObject( $result ) {
 142                 if ( !$result ) {
 143                         return false;
 144                 } elseif ( $result instanceof MssqlResultWrapper ) {
 145                         return $result;
 146                 } elseif ( $result === true ) {
 147                         // Successful write query
 148                         return $result;
 149                 } else {
 150                         return new MssqlResultWrapper( $this, $result );
 151                 }
 152         }
 153
 154         /**
 155          * @param string $sql
 156          * @return bool|MssqlResult
 157          * @throws DBUnexpectedError
 158          */
 159         protected function doQuery( $sql ) {
 160                 if ( $this->getFlag( DBO_DEBUG ) ) {
 161                         wfDebug( "SQL: [$sql]\n" );
 162                 }
 163                 $this->offset = 0;
 164
 165                 // several extensions seem to think that all databases support limits
 166                 // via LIMIT N after the WHERE clause well, MSSQL uses SELECT TOP N,
 167                 // so to catch any of those extensions we'll do a quick check for a
 168                 // LIMIT clause and pass $sql through $this->LimitToTopN() which parses
 169                 // the limit clause and passes the result to $this->limitResult();
 170                 if ( preg_match( '/\bLIMIT\s*/i', $sql ) ) {
 171                         // massage LIMIT -> TopN
 172                         $sql = $this->LimitToTopN( $sql );
 173                 }
 174
 175                 // MSSQL doesn't have EXTRACT(epoch FROM XXX)
 176                 if ( preg_match( '#\bEXTRACT\s*?\(\s*?EPOCH\s+FROM\b#i', $sql, $matches ) ) {
 177                         // This is same as UNIX_TIMESTAMP, we need to calc # of seconds from 1970
 178                         $sql = str_replace( $matches[0], "DATEDIFF(s,CONVERT(datetime,'1/1/1970'),", $sql );
 179                 }
 180
 181                 // perform query
 182
 183                 // SQLSRV_CURSOR_STATIC is slower than SQLSRV_CURSOR_CLIENT_BUFFERED (one of the two is
 184                 // needed if we want to be able to seek around the result set), however CLIENT_BUFFERED
 185                 // has a bug in the sqlsrv driver where wchar_t types (such as nvarchar) that are empty
 186                 // strings make php throw a fatal error "Severe error translating Unicode"
 187                 if ( $this->mScrollableCursor ) {
 188                         $scrollArr = [ 'Scrollable' => SQLSRV_CURSOR_STATIC ];
 189                 } else {
 190                         $scrollArr = [];
 191                 }
 192
 193                 if ( $this->mPrepareStatements ) {
 194                         // we do prepare + execute so we can get its field metadata for later usage if desired
 195                         $stmt = sqlsrv_prepare( $this->mConn, $sql, [], $scrollArr );
 196                         $success = sqlsrv_execute( $stmt );
 197                 } else {
 198                         $stmt = sqlsrv_query( $this->mConn, $sql, [], $scrollArr );
 199                         $success = (bool)$stmt;
 200                 }
 201
 202                 // make a copy so that anything we add below does not get reflected in future queries
 203                 $ignoreErrors = $this->mIgnoreErrors;
 204
 205                 if ( $this->mIgnoreDupKeyErrors ) {
 206                         // ignore duplicate key errors
 207                         // this emulates INSERT IGNORE in MySQL
 208                         $ignoreErrors[] = '2601'; // duplicate key error caused by unique index
 209                         $ignoreErrors[] = '2627'; // duplicate key error caused by primary key
 210                         $ignoreErrors[] = '3621'; // generic "the statement has been terminated" error
 211                 }
 212
 213                 if ( $success === false ) {
 214                         $errors = sqlsrv_errors();
 215                         $success = true;
 216
 217                         foreach ( $errors as $err ) {
 218                                 if ( !in_array( $err['code'], $ignoreErrors ) ) {
 219                                         $success = false;
 220                                         break;
 221                                 }
 222                         }
 223
 224                         if ( $success === false ) {
 225                                 return false;
 226                         }
 227                 }
 228                 // remember number of rows affected
 229                 $this->mAffectedRows = sqlsrv_rows_affected( $stmt );
 230
 231                 return $stmt;
 232         }
 233
 234         public function freeResult( $res ) {
 235                 if ( $res instanceof ResultWrapper ) {
 236                         $res = $res->result;
 237                 }
 238
 239                 sqlsrv_free_stmt( $res );
 240         }
 241
 242         /**
 243          * @param MssqlResultWrapper $res
 244          * @return stdClass
 245          */
 246         public function fetchObject( $res ) {
 247                 // $res is expected to be an instance of MssqlResultWrapper here
 248                 return $res->fetchObject();
 249         }
 250
 251         /**
 252          * @param MssqlResultWrapper $res
 253          * @return array
 254          */
 255         public function fetchRow( $res ) {
 256                 return $res->fetchRow();
 257         }
 258
 259         /**
 260          * @param mixed $res
 261          * @return int
 262          */
 263         public function numRows( $res ) {
 264                 if ( $res instanceof ResultWrapper ) {
 265                         $res = $res->result;
 266                 }
 267
 268                 $ret = sqlsrv_num_rows( $res );
 269
 270                 if ( $ret === false ) {
 271                         // we cannot get an amount of rows from this cursor type
 272                         // has_rows returns bool true/false if the result has rows
 273                         $ret = (int)sqlsrv_has_rows( $res );
 274                 }
 275
 276                 return $ret;
 277         }
 278
 279         /**
 280          * @param mixed $res
 281          * @return int
 282          */
 283         public function numFields( $res ) {
 284                 if ( $res instanceof ResultWrapper ) {
 285                         $res = $res->result;
 286                 }
 287
 288                 return sqlsrv_num_fields( $res );
 289         }
 290
 291         /**
 292          * @param mixed $res
 293          * @param int $n
 294          * @return int
 295          */
 296         public function fieldName( $res, $n ) {
 297                 if ( $res instanceof ResultWrapper ) {
 298                         $res = $res->result;
 299                 }
 300
 301                 return sqlsrv_field_metadata( $res )[$n]['Name'];
 302         }
 303
 304         /**
 305          * This must be called after nextSequenceVal
 306          * @return int|null
 307          */
 308         public function insertId() {
 309                 return $this->mInsertId;
 310         }
 311
 312         /**
 313          * @param MssqlResultWrapper $res
 314          * @param int $row
 315          * @return bool
 316          */
 317         public function dataSeek( $res, $row ) {
 318                 return $res->seek( $row );
 319         }
 320
 321         /**
 322          * @return string
 323          */
 324         public function lastError() {
 325                 $strRet = '';
 326                 $retErrors = sqlsrv_errors( SQLSRV_ERR_ALL );
 327                 if ( $retErrors != null ) {
 328                         foreach ( $retErrors as $arrError ) {
 329                                 $strRet .= $this->formatError( $arrError ) . "\n";
 330                         }
 331                 } else {
 332                         $strRet = "No errors found";
 333                 }
 334
 335                 return $strRet;
 336         }
 337
 338         /**
 339          * @param array $err
 340          * @return string
 341          */
 342         private function formatError( $err ) {
 343                 return '[SQLSTATE ' . $err['SQLSTATE'] . '][Error Code ' . $err['code'] . ']' . $err['message'];
 344         }
 345
 346         /**
 347          * @return string
 348          */
 349         public function lastErrno() {
 350                 $err = sqlsrv_errors( SQLSRV_ERR_ALL );
 351                 if ( $err !== null && isset( $err[0] ) ) {
 352                         return $err[0]['code'];
 353                 } else {
 354                         return 0;
 355                 }
 356         }
 357
 358         /**
 359          * @return int
 360          */
 361         public function affectedRows() {
 362                 return $this->mAffectedRows;
 363         }
 364
 365         /**
 366          * SELECT wrapper
 367          *
 368          * @param mixed $table Array or string, table name(s) (prefix auto-added)
 369          * @param mixed $vars Array or string, field name(s) to be retrieved
 370          * @param mixed $conds Array or string, condition(s) for WHERE
 371          * @param string $fname Calling function name (use __METHOD__) for logs/profiling
 372          * @param array $options Associative array of options (e.g.
 373          *   [ 'GROUP BY' => 'page_title' ]), see Database::makeSelectOptions
 374          *   code for list of supported stuff
 375          * @param array $join_conds Associative array of table join conditions
 376          *   (optional) (e.g. [ 'page' => [ 'LEFT JOIN','page_latest=rev_id' ] ]
 377          * @return mixed Database result resource (feed to Database::fetchObject
 378          *   or whatever), or false on failure
 379          * @throws DBQueryError
 380          * @throws DBUnexpectedError
 381          * @throws Exception
 382          */
 383         public function select( $table, $vars, $conds = '', $fname = __METHOD__,
 384                 $options = [], $join_conds = []
 385         ) {
 386                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 387                 if ( isset( $options['EXPLAIN'] ) ) {
 388                         try {
 389                                 $this->mScrollableCursor = false;
 390                                 $this->mPrepareStatements = false;
 391                                 $this->query( "SET SHOWPLAN_ALL ON" );
 392                                 $ret = $this->query( $sql, $fname );
 393                                 $this->query( "SET SHOWPLAN_ALL OFF" );
 394                         } catch ( DBQueryError $dqe ) {
 395                                 if ( isset( $options['FOR COUNT'] ) ) {
 396                                         // likely don't have privs for SHOWPLAN, so run a select count instead
 397                                         $this->query( "SET SHOWPLAN_ALL OFF" );
 398                                         unset( $options['EXPLAIN'] );
 399                                         $ret = $this->select(
 400                                                 $table,
 401                                                 'COUNT(*) AS EstimateRows',
 402                                                 $conds,
 403                                                 $fname,
 404                                                 $options,
 405                                                 $join_conds
 406                                         );
 407                                 } else {
 408                                         // someone actually wanted the query plan instead of an est row count
 409                                         // let them know of the error
 410                                         $this->mScrollableCursor = true;
 411                                         $this->mPrepareStatements = true;
 412                                         throw $dqe;
 413                                 }
 414                         }
 415                         $this->mScrollableCursor = true;
 416                         $this->mPrepareStatements = true;
 417                         return $ret;
 418                 }
 419                 return $this->query( $sql, $fname );
 420         }
 421
 422         /**
 423          * SELECT wrapper
 424          *
 425          * @param mixed $table Array or string, table name(s) (prefix auto-added)
 426          * @param mixed $vars Array or string, field name(s) to be retrieved
 427          * @param mixed $conds Array or string, condition(s) for WHERE
 428          * @param string $fname Calling function name (use __METHOD__) for logs/profiling
 429          * @param array $options Associative array of options (e.g. [ 'GROUP BY' => 'page_title' ]),
 430          *   see Database::makeSelectOptions code for list of supported stuff
 431          * @param array $join_conds Associative array of table join conditions (optional)
 432          *    (e.g. [ 'page' => [ 'LEFT JOIN','page_latest=rev_id' ] ]
 433          * @return string The SQL text
 434          */
 435         public function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 436                 $options = [], $join_conds = []
 437         ) {
 438                 if ( isset( $options['EXPLAIN'] ) ) {
 439                         unset( $options['EXPLAIN'] );
 440                 }
 441
 442                 $sql = parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 443
 444                 // try to rewrite aggregations of bit columns (currently MAX and MIN)
 445                 if ( strpos( $sql, 'MAX(' ) !== false || strpos( $sql, 'MIN(' ) !== false ) {
 446                         $bitColumns = [];
 447                         if ( is_array( $table ) ) {
 448                                 foreach ( $table as $t ) {
 449                                         $bitColumns += $this->getBitColumns( $this->tableName( $t ) );
 450                                 }
 451                         } else {
 452                                 $bitColumns = $this->getBitColumns( $this->tableName( $table ) );
 453                         }
 454
 455                         foreach ( $bitColumns as $col => $info ) {
 456                                 $replace = [
 457                                         "MAX({$col})" => "MAX(CAST({$col} AS tinyint))",
 458                                         "MIN({$col})" => "MIN(CAST({$col} AS tinyint))",
 459                                 ];
 460                                 $sql = str_replace( array_keys( $replace ), array_values( $replace ), $sql );
 461                         }
 462                 }
 463
 464                 return $sql;
 465         }
 466
 467         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
 468                 $fname = __METHOD__
 469         ) {
 470                 $this->mScrollableCursor = false;
 471                 try {
 472                         parent::deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname );
 473                 } catch ( Exception $e ) {
 474                         $this->mScrollableCursor = true;
 475                         throw $e;
 476                 }
 477                 $this->mScrollableCursor = true;
 478         }
 479
 480         public function delete( $table, $conds, $fname = __METHOD__ ) {
 481                 $this->mScrollableCursor = false;
 482                 try {
 483                         parent::delete( $table, $conds, $fname );
 484                 } catch ( Exception $e ) {
 485                         $this->mScrollableCursor = true;
 486                         throw $e;
 487                 }
 488                 $this->mScrollableCursor = true;
 489         }
 490
 491         /**
 492          * Estimate rows in dataset
 493          * Returns estimated count, based on SHOWPLAN_ALL output
 494          * This is not necessarily an accurate estimate, so use sparingly
 495          * Returns -1 if count cannot be found
 496          * Takes same arguments as Database::select()
 497          * @param string $table
 498          * @param string $vars
 499          * @param string $conds
 500          * @param string $fname
 501          * @param array $options
 502          * @return int
 503          */
 504         public function estimateRowCount( $table, $vars = '*', $conds = '',
 505                 $fname = __METHOD__, $options = []
 506         ) {
 507                 // http://msdn2.microsoft.com/en-us/library/aa259203.aspx
 508                 $options['EXPLAIN'] = true;
 509                 $options['FOR COUNT'] = true;
 510                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 511
 512                 $rows = -1;
 513                 if ( $res ) {
 514                         $row = $this->fetchRow( $res );
 515
 516                         if ( isset( $row['EstimateRows'] ) ) {
 517                                 $rows = (int)$row['EstimateRows'];
 518                         }
 519                 }
 520
 521                 return $rows;
 522         }
 523
 524         /**
 525          * Returns information about an index
 526          * If errors are explicitly ignored, returns NULL on failure
 527          * @param string $table
 528          * @param string $index
 529          * @param string $fname
 530          * @return array|bool|null
 531          */
 532         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 533                 # This does not return the same info as MYSQL would, but that's OK
 534                 # because MediaWiki never uses the returned value except to check for
 535                 # the existance of indexes.
 536                 $sql = "sp_helpindex '" . $this->tableName( $table ) . "'";
 537                 $res = $this->query( $sql, $fname );
 538
 539                 if ( !$res ) {
 540                         return null;
 541                 }
 542
 543                 $result = [];
 544                 foreach ( $res as $row ) {
 545                         if ( $row->index_name == $index ) {
 546                                 $row->Non_unique = !stristr( $row->index_description, "unique" );
 547                                 $cols = explode( ", ", $row->index_keys );
 548                                 foreach ( $cols as $col ) {
 549                                         $row->Column_name = trim( $col );
 550                                         $result[] = clone $row;
 551                                 }
 552                         } elseif ( $index == 'PRIMARY' && stristr( $row->index_description, 'PRIMARY' ) ) {
 553                                 $row->Non_unique = 0;
 554                                 $cols = explode( ", ", $row->index_keys );
 555                                 foreach ( $cols as $col ) {
 556                                         $row->Column_name = trim( $col );
 557                                         $result[] = clone $row;
 558                                 }
 559                         }
 560                 }
 561
 562                 return empty( $result ) ? false : $result;
 563         }
 564
 565         /**
 566          * INSERT wrapper, inserts an array into a table
 567          *
 568          * $arrToInsert may be a single associative array, or an array of these with numeric keys, for
 569          * multi-row insert.
 570          *
 571          * Usually aborts on failure
 572          * If errors are explicitly ignored, returns success
 573          * @param string $table
 574          * @param array $arrToInsert
 575          * @param string $fname
 576          * @param array $options
 577          * @return bool
 578          * @throws Exception
 579          */
 580         public function insert( $table, $arrToInsert, $fname = __METHOD__, $options = [] ) {
 581                 # No rows to insert, easy just return now
 582                 if ( !count( $arrToInsert ) ) {
 583                         return true;
 584                 }
 585
 586                 if ( !is_array( $options ) ) {
 587                         $options = [ $options ];
 588                 }
 589
 590                 $table = $this->tableName( $table );
 591
 592                 if ( !( isset( $arrToInsert[0] ) && is_array( $arrToInsert[0] ) ) ) { // Not multi row
 593                         $arrToInsert = [ 0 => $arrToInsert ]; // make everything multi row compatible
 594                 }
 595
 596                 // We know the table we're inserting into, get its identity column
 597                 $identity = null;
 598                 // strip matching square brackets and the db/schema from table name
 599                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
 600                 $tableRaw = array_pop( $tableRawArr );
 601                 $res = $this->doQuery(
 602                         "SELECT NAME AS idColumn FROM SYS.IDENTITY_COLUMNS " .
 603                                 "WHERE OBJECT_NAME(OBJECT_ID)='{$tableRaw}'"
 604                 );
 605                 if ( $res && sqlsrv_has_rows( $res ) ) {
 606                         // There is an identity for this table.
 607                         $identityArr = sqlsrv_fetch_array( $res, SQLSRV_FETCH_ASSOC );
 608                         $identity = array_pop( $identityArr );
 609                 }
 610                 sqlsrv_free_stmt( $res );
 611
 612                 // Determine binary/varbinary fields so we can encode data as a hex string like 0xABCDEF
 613                 $binaryColumns = $this->getBinaryColumns( $table );
 614
 615                 // INSERT IGNORE is not supported by SQL Server
 616                 // remove IGNORE from options list and set ignore flag to true
 617                 if ( in_array( 'IGNORE', $options ) ) {
 618                         $options = array_diff( $options, [ 'IGNORE' ] );
 619                         $this->mIgnoreDupKeyErrors = true;
 620                 }
 621
 622                 foreach ( $arrToInsert as $a ) {
 623                         // start out with empty identity column, this is so we can return
 624                         // it as a result of the insert logic
 625                         $sqlPre = '';
 626                         $sqlPost = '';
 627                         $identityClause = '';
 628
 629                         // if we have an identity column
 630                         if ( $identity ) {
 631                                 // iterate through
 632                                 foreach ( $a as $k => $v ) {
 633                                         if ( $k == $identity ) {
 634                                                 if ( !is_null( $v ) ) {
 635                                                         // there is a value being passed to us,
 636                                                         // we need to turn on and off inserted identity
 637                                                         $sqlPre = "SET IDENTITY_INSERT $table ON;";
 638                                                         $sqlPost = ";SET IDENTITY_INSERT $table OFF;";
 639                                                 } else {
 640                                                         // we can't insert NULL into an identity column,
 641                                                         // so remove the column from the insert.
 642                                                         unset( $a[$k] );
 643                                                 }
 644                                         }
 645                                 }
 646
 647                                 // we want to output an identity column as result
 648                                 $identityClause = "OUTPUT INSERTED.$identity ";
 649                         }
 650
 651                         $keys = array_keys( $a );
 652
 653                         // Build the actual query
 654                         $sql = $sqlPre . 'INSERT ' . implode( ' ', $options ) .
 655                                 " INTO $table (" . implode( ',', $keys ) . ") $identityClause VALUES (";
 656
 657                         $first = true;
 658                         foreach ( $a as $key => $value ) {
 659                                 if ( isset( $binaryColumns[$key] ) ) {
 660                                         $value = new MssqlBlob( $value );
 661                                 }
 662                                 if ( $first ) {
 663                                         $first = false;
 664                                 } else {
 665                                         $sql .= ',';
 666                                 }
 667                                 if ( is_null( $value ) ) {
 668                                         $sql .= 'null';
 669                                 } elseif ( is_array( $value ) || is_object( $value ) ) {
 670                                         if ( is_object( $value ) && $value instanceof Blob ) {
 671                                                 $sql .= $this->addQuotes( $value );
 672                                         } else {
 673                                                 $sql .= $this->addQuotes( serialize( $value ) );
 674                                         }
 675                                 } else {
 676                                         $sql .= $this->addQuotes( $value );
 677                                 }
 678                         }
 679                         $sql .= ')' . $sqlPost;
 680
 681                         // Run the query
 682                         $this->mScrollableCursor = false;
 683                         try {
 684                                 $ret = $this->query( $sql );
 685                         } catch ( Exception $e ) {
 686                                 $this->mScrollableCursor = true;
 687                                 $this->mIgnoreDupKeyErrors = false;
 688                                 throw $e;
 689                         }
 690                         $this->mScrollableCursor = true;
 691
 692                         if ( !is_null( $identity ) ) {
 693                                 // then we want to get the identity column value we were assigned and save it off
 694                                 $row = $ret->fetchObject();
 695                                 if ( is_object( $row ) ) {
 696                                         $this->mInsertId = $row->$identity;
 697
 698                                         // it seems that mAffectedRows is -1 sometimes when OUTPUT INSERTED.identity is used
 699                                         // if we got an identity back, we know for sure a row was affected, so adjust that here
 700                                         if ( $this->mAffectedRows == -1 ) {
 701                                                 $this->mAffectedRows = 1;
 702                                         }
 703                                 }
 704                         }
 705                 }
 706                 $this->mIgnoreDupKeyErrors = false;
 707                 return $ret;
 708         }
 709
 710         /**
 711          * INSERT SELECT wrapper
 712          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 713          * Source items may be literals rather than field names, but strings should
 714          * be quoted with Database::addQuotes().
 715          * @param string $destTable
 716          * @param array|string $srcTable May be an array of tables.
 717          * @param array $varMap
 718          * @param array $conds May be "*" to copy the whole table.
 719          * @param string $fname
 720          * @param array $insertOptions
 721          * @param array $selectOptions
 722          * @return null|ResultWrapper
 723          * @throws Exception
 724          */
 725         public function nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 726                 $insertOptions = [], $selectOptions = []
 727         ) {
 728                 $this->mScrollableCursor = false;
 729                 try {
 730                         $ret = parent::nativeInsertSelect(
 731                                 $destTable,
 732                                 $srcTable,
 733                                 $varMap,
 734                                 $conds,
 735                                 $fname,
 736                                 $insertOptions,
 737                                 $selectOptions
 738                         );
 739                 } catch ( Exception $e ) {
 740                         $this->mScrollableCursor = true;
 741                         throw $e;
 742                 }
 743                 $this->mScrollableCursor = true;
 744
 745                 return $ret;
 746         }
 747
 748         /**
 749          * UPDATE wrapper. Takes a condition array and a SET array.
 750          *
 751          * @param string $table Name of the table to UPDATE. This will be passed through
 752          *                DatabaseBase::tableName().
 753          *
 754          * @param array $values An array of values to SET. For each array element,
 755          *                the key gives the field name, and the value gives the data
 756          *                to set that field to. The data will be quoted by
 757          *                DatabaseBase::addQuotes().
 758          *
 759          * @param array $conds An array of conditions (WHERE). See
 760          *                DatabaseBase::select() for the details of the format of
 761          *                condition arrays. Use '*' to update all rows.
 762          *
 763          * @param string $fname The function name of the caller (from __METHOD__),
 764          *                for logging and profiling.
 765          *
 766          * @param array $options An array of UPDATE options, can be:
 767          *                   - IGNORE: Ignore unique key conflicts
 768          *                   - LOW_PRIORITY: MySQL-specific, see MySQL manual.
 769          * @return bool
 770          * @throws DBUnexpectedError
 771          * @throws Exception
 772          */
 773         function update( $table, $values, $conds, $fname = __METHOD__, $options = [] ) {
 774                 $table = $this->tableName( $table );
 775                 $binaryColumns = $this->getBinaryColumns( $table );
 776
 777                 $opts = $this->makeUpdateOptions( $options );
 778                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET, $binaryColumns );
 779
 780                 if ( $conds !== [] && $conds !== '*' ) {
 781                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND, $binaryColumns );
 782                 }
 783
 784                 $this->mScrollableCursor = false;
 785                 try {
 786                         $ret = $this->query( $sql );
 787                 } catch ( Exception $e ) {
 788                         $this->mScrollableCursor = true;
 789                         throw $e;
 790                 }
 791                 $this->mScrollableCursor = true;
 792                 return true;
 793         }
 794
 795         /**
 796          * Makes an encoded list of strings from an array
 797          * @param array $a Containing the data
 798          * @param int $mode Constant
 799          *      - LIST_COMMA:          comma separated, no field names
 800          *      - LIST_AND:            ANDed WHERE clause (without the WHERE). See
 801          *        the documentation for $conds in DatabaseBase::select().
 802          *      - LIST_OR:             ORed WHERE clause (without the WHERE)
 803          *      - LIST_SET:            comma separated with field names, like a SET clause
 804          *      - LIST_NAMES:          comma separated field names
 805          * @param array $binaryColumns Contains a list of column names that are binary types
 806          *      This is a custom parameter only present for MS SQL.
 807          *
 808          * @throws DBUnexpectedError
 809          * @return string
 810          */
 811         public function makeList( $a, $mode = LIST_COMMA, $binaryColumns = [] ) {
 812                 if ( !is_array( $a ) ) {
 813                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with incorrect parameters' );
 814                 }
 815
 816                 if ( $mode != LIST_NAMES ) {
 817                         // In MS SQL, values need to be specially encoded when they are
 818                         // inserted into binary fields. Perform this necessary encoding
 819                         // for the specified set of columns.
 820                         foreach ( array_keys( $a ) as $field ) {
 821                                 if ( !isset( $binaryColumns[$field] ) ) {
 822                                         continue;
 823                                 }
 824
 825                                 if ( is_array( $a[$field] ) ) {
 826                                         foreach ( $a[$field] as &$v ) {
 827                                                 $v = new MssqlBlob( $v );
 828                                         }
 829                                         unset( $v );
 830                                 } else {
 831                                         $a[$field] = new MssqlBlob( $a[$field] );
 832                                 }
 833                         }
 834                 }
 835
 836                 return parent::makeList( $a, $mode );
 837         }
 838
 839         /**
 840          * @param string $table
 841          * @param string $field
 842          * @return int Returns the size of a text field, or -1 for "unlimited"
 843          */
 844         public function textFieldSize( $table, $field ) {
 845                 $table = $this->tableName( $table );
 846                 $sql = "SELECT CHARACTER_MAXIMUM_LENGTH,DATA_TYPE FROM INFORMATION_SCHEMA.Columns
 847                         WHERE TABLE_NAME = '$table' AND COLUMN_NAME = '$field'";
 848                 $res = $this->query( $sql );
 849                 $row = $this->fetchRow( $res );
 850                 $size = -1;
 851                 if ( strtolower( $row['DATA_TYPE'] ) != 'text' ) {
 852                         $size = $row['CHARACTER_MAXIMUM_LENGTH'];
 853                 }
 854
 855                 return $size;
 856         }
 857
 858         /**
 859          * Construct a LIMIT query with optional offset
 860          * This is used for query pages
 861          *
 862          * @param string $sql SQL query we will append the limit too
 863          * @param int $limit The SQL limit
 864          * @param bool|int $offset The SQL offset (default false)
 865          * @return array|string
 866          * @throws DBUnexpectedError
 867          */
 868         public function limitResult( $sql, $limit, $offset = false ) {
 869                 if ( $offset === false || $offset == 0 ) {
 870                         if ( strpos( $sql, "SELECT" ) === false ) {
 871                                 return "TOP {$limit} " . $sql;
 872                         } else {
 873                                 return preg_replace( '/\bSELECT(\s+DISTINCT)?\b/Dsi',
 874                                         'SELECT$1 TOP ' . $limit, $sql, 1 );
 875                         }
 876                 } else {
 877                         // This one is fun, we need to pull out the select list as well as any ORDER BY clause
 878                         $select = $orderby = [];
 879                         $s1 = preg_match( '#SELECT\s+(.+?)\s+FROM#Dis', $sql, $select );
 880                         $s2 = preg_match( '#(ORDER BY\s+.+?)(\s*FOR XML .*)?$#Dis', $sql, $orderby );
 881                         $overOrder = $postOrder = '';
 882                         $first = $offset + 1;
 883                         $last = $offset + $limit;
 884                         $sub1 = 'sub_' . $this->mSubqueryId;
 885                         $sub2 = 'sub_' . ( $this->mSubqueryId + 1 );
 886                         $this->mSubqueryId += 2;
 887                         if ( !$s1 ) {
 888                                 // wat
 889                                 throw new DBUnexpectedError( $this, "Attempting to LIMIT a non-SELECT query\n" );
 890                         }
 891                         if ( !$s2 ) {
 892                                 // no ORDER BY
 893                                 $overOrder = 'ORDER BY (SELECT 1)';
 894                         } else {
 895                                 if ( !isset( $orderby[2] ) || !$orderby[2] ) {
 896                                         // don't need to strip it out if we're using a FOR XML clause
 897                                         $sql = str_replace( $orderby[1], '', $sql );
 898                                 }
 899                                 $overOrder = $orderby[1];
 900                                 $postOrder = ' ' . $overOrder;
 901                         }
 902                         $sql = "SELECT {$select[1]}
 903                                         FROM (
 904                                                 SELECT ROW_NUMBER() OVER({$overOrder}) AS rowNumber, *
 905                                                 FROM ({$sql}) {$sub1}
 906                                         ) {$sub2}
 907                                         WHERE rowNumber BETWEEN {$first} AND {$last}{$postOrder}";
 908
 909                         return $sql;
 910                 }
 911         }
 912
 913         /**
 914          * If there is a limit clause, parse it, strip it, and pass the remaining
 915          * SQL through limitResult() with the appropriate parameters. Not the
 916          * prettiest solution, but better than building a whole new parser. This
 917          * exists becase there are still too many extensions that don't use dynamic
 918          * sql generation.
 919          *
 920          * @param string $sql
 921          * @return array|mixed|string
 922          */
 923         public function LimitToTopN( $sql ) {
 924                 // Matches: LIMIT {[offset,] row_count | row_count OFFSET offset}
 925                 $pattern = '/\bLIMIT\s+((([0-9]+)\s*,\s*)?([0-9]+)(\s+OFFSET\s+([0-9]+))?)/i';
 926                 if ( preg_match( $pattern, $sql, $matches ) ) {
 927                         $row_count = $matches[4];
 928                         $offset = $matches[3] ?: $matches[6] ?: false;
 929
 930                         // strip the matching LIMIT clause out
 931                         $sql = str_replace( $matches[0], '', $sql );
 932
 933                         return $this->limitResult( $sql, $row_count, $offset );
 934                 }
 935
 936                 return $sql;
 937         }
 938
 939         /**
 940          * @return string Wikitext of a link to the server software's web site
 941          */
 942         public function getSoftwareLink() {
 943                 return "[{{int:version-db-mssql-url}} MS SQL Server]";
 944         }
 945
 946         /**
 947          * @return string Version information from the database
 948          */
 949         public function getServerVersion() {
 950                 $server_info = sqlsrv_server_info( $this->mConn );
 951                 $version = 'Error';
 952                 if ( isset( $server_info['SQLServerVersion'] ) ) {
 953                         $version = $server_info['SQLServerVersion'];
 954                 }
 955
 956                 return $version;
 957         }
 958
 959         /**
 960          * @param string $table
 961          * @param string $fname
 962          * @return bool
 963          */
 964         public function tableExists( $table, $fname = __METHOD__ ) {
 965                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
 966
 967                 if ( $db !== false ) {
 968                         // remote database
 969                         wfDebug( "Attempting to call tableExists on a remote table" );
 970                         return false;
 971                 }
 972
 973                 if ( $schema === false ) {
 974                         global $wgDBmwschema;
 975                         $schema = $wgDBmwschema;
 976                 }
 977
 978                 $res = $this->query( "SELECT 1 FROM INFORMATION_SCHEMA.TABLES
 979                         WHERE TABLE_TYPE = 'BASE TABLE'
 980                         AND TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table'" );
 981
 982                 if ( $res->numRows() ) {
 983                         return true;
 984                 } else {
 985                         return false;
 986                 }
 987         }
 988
 989         /**
 990          * Query whether a given column exists in the mediawiki schema
 991          * @param string $table
 992          * @param string $field
 993          * @param string $fname
 994          * @return bool
 995          */
 996         public function fieldExists( $table, $field, $fname = __METHOD__ ) {
 997                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
 998
 999                 if ( $db !== false ) {
1000                         // remote database
1001                         wfDebug( "Attempting to call fieldExists on a remote table" );
1002                         return false;
1003                 }
1004
1005                 $res = $this->query( "SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS
1006                         WHERE TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table' AND COLUMN_NAME = '$field'" );
1007
1008                 if ( $res->numRows() ) {
1009                         return true;
1010                 } else {
1011                         return false;
1012                 }
1013         }
1014
1015         public function fieldInfo( $table, $field ) {
1016                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
1017
1018                 if ( $db !== false ) {
1019                         // remote database
1020                         wfDebug( "Attempting to call fieldInfo on a remote table" );
1021                         return false;
1022                 }
1023
1024                 $res = $this->query( "SELECT * FROM INFORMATION_SCHEMA.COLUMNS
1025                         WHERE TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table' AND COLUMN_NAME = '$field'" );
1026
1027                 $meta = $res->fetchRow();
1028                 if ( $meta ) {
1029                         return new MssqlField( $meta );
1030                 }
1031
1032                 return false;
1033         }
1034
1035         /**
1036          * Begin a transaction, committing any previously open transaction
1037          * @param string $fname
1038          */
1039         protected function doBegin( $fname = __METHOD__ ) {
1040                 sqlsrv_begin_transaction( $this->mConn );
1041                 $this->mTrxLevel = 1;
1042         }
1043
1044         /**
1045          * End a transaction
1046          * @param string $fname
1047          */
1048         protected function doCommit( $fname = __METHOD__ ) {
1049                 sqlsrv_commit( $this->mConn );
1050                 $this->mTrxLevel = 0;
1051         }
1052
1053         /**
1054          * Rollback a transaction.
1055          * No-op on non-transactional databases.
1056          * @param string $fname
1057          */
1058         protected function doRollback( $fname = __METHOD__ ) {
1059                 sqlsrv_rollback( $this->mConn );
1060                 $this->mTrxLevel = 0;
1061         }
1062
1063         /**
1064          * Escapes a identifier for use inm SQL.
1065          * Throws an exception if it is invalid.
1066          * Reference: http://msdn.microsoft.com/en-us/library/aa224033%28v=SQL.80%29.aspx
1067          * @param string $identifier
1068          * @throws InvalidArgumentException
1069          * @return string
1070          */
1071         private function escapeIdentifier( $identifier ) {
1072                 if ( strlen( $identifier ) == 0 ) {
1073                         throw new InvalidArgumentException( "An identifier must not be empty" );
1074                 }
1075                 if ( strlen( $identifier ) > 128 ) {
1076                         throw new InvalidArgumentException( "The identifier '$identifier' is too long (max. 128)" );
1077                 }
1078                 if ( ( strpos( $identifier, '[' ) !== false )
1079                         || ( strpos( $identifier, ']' ) !== false )
1080                 ) {
1081                         // It may be allowed if you quoted with double quotation marks, but
1082                         // that would break if QUOTED_IDENTIFIER is OFF
1083                         throw new InvalidArgumentException( "Square brackets are not allowed in '$identifier'" );
1084                 }
1085
1086                 return "[$identifier]";
1087         }
1088
1089         /**
1090          * @param string $s
1091          * @return string
1092          */
1093         public function strencode( $s ) {
1094                 // Should not be called by us
1095
1096                 return str_replace( "'", "''", $s );
1097         }
1098
1099         /**
1100          * @param string|Blob $s
1101          * @return string
1102          */
1103         public function addQuotes( $s ) {
1104                 if ( $s instanceof MssqlBlob ) {
1105                         return $s->fetch();
1106                 } elseif ( $s instanceof Blob ) {
1107                         // this shouldn't really ever be called, but it's here if needed
1108                         // (and will quite possibly make the SQL error out)
1109                         $blob = new MssqlBlob( $s->fetch() );
1110                         return $blob->fetch();
1111                 } else {
1112                         if ( is_bool( $s ) ) {
1113                                 $s = $s ? 1 : 0;
1114                         }
1115                         return parent::addQuotes( $s );
1116                 }
1117         }
1118
1119         /**
1120          * @param string $s
1121          * @return string
1122          */
1123         public function addIdentifierQuotes( $s ) {
1124                 // http://msdn.microsoft.com/en-us/library/aa223962.aspx
1125                 return '[' . $s . ']';
1126         }
1127
1128         /**
1129          * @param string $name
1130          * @return bool
1131          */
1132         public function isQuotedIdentifier( $name ) {
1133                 return strlen( $name ) && $name[0] == '[' && substr( $name, -1, 1 ) == ']';
1134         }
1135
1136         /**
1137          * MS SQL supports more pattern operators than other databases (ex: [,],^)
1138          *
1139          * @param string $s
1140          * @return string
1141          */
1142         protected function escapeLikeInternal( $s ) {
1143                 return addcslashes( $s, '\%_[]^' );
1144         }
1145
1146         /**
1147          * MS SQL requires specifying the escape character used in a LIKE query
1148          * or using Square brackets to surround characters that are to be escaped
1149          * http://msdn.microsoft.com/en-us/library/ms179859.aspx
1150          * Here we take the Specify-Escape-Character approach since it's less
1151          * invasive, renders a query that is closer to other DB's and better at
1152          * handling square bracket escaping
1153          *
1154          * @return string Fully built LIKE statement
1155          */
1156         public function buildLike() {
1157                 $params = func_get_args();
1158                 if ( count( $params ) > 0 && is_array( $params[0] ) ) {
1159                         $params = $params[0];
1160                 }
1161
1162                 return parent::buildLike( $params ) . " ESCAPE '\' ";
1163         }
1164
1165         /**
1166          * @param string $db
1167          * @return bool
1168          */
1169         public function selectDB( $db ) {
1170                 try {
1171                         $this->mDBname = $db;
1172                         $this->query( "USE $db" );
1173                         return true;
1174                 } catch ( Exception $e ) {
1175                         return false;
1176                 }
1177         }
1178
1179         /**
1180          * @param array $options An associative array of options to be turned into
1181          *   an SQL query, valid keys are listed in the function.
1182          * @return array
1183          */
1184         public function makeSelectOptions( $options ) {
1185                 $tailOpts = '';
1186                 $startOpts = '';
1187
1188                 $noKeyOptions = [];
1189                 foreach ( $options as $key => $option ) {
1190                         if ( is_numeric( $key ) ) {
1191                                 $noKeyOptions[$option] = true;
1192                         }
1193                 }
1194
1195                 $tailOpts .= $this->makeGroupByWithHaving( $options );
1196
1197                 $tailOpts .= $this->makeOrderBy( $options );
1198
1199                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1200                         $startOpts .= 'DISTINCT';
1201                 }
1202
1203                 if ( isset( $noKeyOptions['FOR XML'] ) ) {
1204                         // used in group concat field emulation
1205                         $tailOpts .= " FOR XML PATH('')";
1206                 }
1207
1208                 // we want this to be compatible with the output of parent::makeSelectOptions()
1209                 return [ $startOpts, '', $tailOpts, '', '' ];
1210         }
1211
1212         /**
1213          * Get the type of the DBMS, as it appears in $wgDBtype.
1214          * @return string
1215          */
1216         public function getType() {
1217                 return 'mssql';
1218         }
1219
1220         /**
1221          * @param array $stringList
1222          * @return string
1223          */
1224         public function buildConcat( $stringList ) {
1225                 return implode( ' + ', $stringList );
1226         }
1227
1228         /**
1229          * Build a GROUP_CONCAT or equivalent statement for a query.
1230          * MS SQL doesn't have GROUP_CONCAT so we emulate it with other stuff (and boy is it nasty)
1231          *
1232          * This is useful for combining a field for several rows into a single string.
1233          * NULL values will not appear in the output, duplicated values will appear,
1234          * and the resulting delimiter-separated values have no defined sort order.
1235          * Code using the results may need to use the PHP unique() or sort() methods.
1236          *
1237          * @param string $delim Glue to bind the results together
1238          * @param string|array $table Table name
1239          * @param string $field Field name
1240          * @param string|array $conds Conditions
1241          * @param string|array $join_conds Join conditions
1242          * @return string SQL text
1243          * @since 1.23
1244          */
1245         public function buildGroupConcatField( $delim, $table, $field, $conds = '',
1246                 $join_conds = []
1247         ) {
1248                 $gcsq = 'gcsq_' . $this->mSubqueryId;
1249                 $this->mSubqueryId++;
1250
1251                 $delimLen = strlen( $delim );
1252                 $fld = "{$field} + {$this->addQuotes( $delim )}";
1253                 $sql = "(SELECT LEFT({$field}, LEN({$field}) - {$delimLen}) FROM ("
1254                         . $this->selectSQLText( $table, $fld, $conds, null, [ 'FOR XML' ], $join_conds )
1255                         . ") {$gcsq} ({$field}))";
1256
1257                 return $sql;
1258         }
1259
1260         /**
1261          * @return string
1262          */
1263         public function getSearchEngine() {
1264                 return "SearchMssql";
1265         }
1266
1267         /**
1268          * Returns an associative array for fields that are of type varbinary, binary, or image
1269          * $table can be either a raw table name or passed through tableName() first
1270          * @param string $table
1271          * @return array
1272          */
1273         private function getBinaryColumns( $table ) {
1274                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
1275                 $tableRaw = array_pop( $tableRawArr );
1276
1277                 if ( $this->mBinaryColumnCache === null ) {
1278                         $this->populateColumnCaches();
1279                 }
1280
1281                 return isset( $this->mBinaryColumnCache[$tableRaw] )
1282                         ? $this->mBinaryColumnCache[$tableRaw]
1283                         : [];
1284         }
1285
1286         /**
1287          * @param string $table
1288          * @return array
1289          */
1290         private function getBitColumns( $table ) {
1291                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
1292                 $tableRaw = array_pop( $tableRawArr );
1293
1294                 if ( $this->mBitColumnCache === null ) {
1295                         $this->populateColumnCaches();
1296                 }
1297
1298                 return isset( $this->mBitColumnCache[$tableRaw] )
1299                         ? $this->mBitColumnCache[$tableRaw]
1300                         : [];
1301         }
1302
1303         private function populateColumnCaches() {
1304                 $res = $this->select( 'INFORMATION_SCHEMA.COLUMNS', '*',
1305                         [
1306                                 'TABLE_CATALOG' => $this->mDBname,
1307                                 'TABLE_SCHEMA' => $this->mSchema,
1308                                 'DATA_TYPE' => [ 'varbinary', 'binary', 'image', 'bit' ]
1309                         ] );
1310
1311                 $this->mBinaryColumnCache = [];
1312                 $this->mBitColumnCache = [];
1313                 foreach ( $res as $row ) {
1314                         if ( $row->DATA_TYPE == 'bit' ) {
1315                                 $this->mBitColumnCache[$row->TABLE_NAME][$row->COLUMN_NAME] = $row;
1316                         } else {
1317                                 $this->mBinaryColumnCache[$row->TABLE_NAME][$row->COLUMN_NAME] = $row;
1318                         }
1319                 }
1320         }
1321
1322         /**
1323          * @param string $name
1324          * @param string $format
1325          * @return string
1326          */
1327         function tableName( $name, $format = 'quoted' ) {
1328                 # Replace reserved words with better ones
1329                 switch ( $name ) {
1330                         case 'user':
1331                                 return $this->realTableName( 'mwuser', $format );
1332                         default:
1333                                 return $this->realTableName( $name, $format );
1334                 }
1335         }
1336
1337         /**
1338          * call this instead of tableName() in the updater when renaming tables
1339          * @param string $name
1340          * @param string $format One of quoted, raw, or split
1341          * @return string
1342          */
1343         function realTableName( $name, $format = 'quoted' ) {
1344                 $table = parent::tableName( $name, $format );
1345                 if ( $format == 'split' ) {
1346                         // Used internally, we want the schema split off from the table name and returned
1347                         // as a list with 3 elements (database, schema, table)
1348                         $table = explode( '.', $table );
1349                         while ( count( $table ) < 3 ) {
1350                                 array_unshift( $table, false );
1351                         }
1352                 }
1353                 return $table;
1354         }
1355
1356         /**
1357          * Delete a table
1358          * @param string $tableName
1359          * @param string $fName
1360          * @return bool|ResultWrapper
1361          * @since 1.18
1362          */
1363         public function dropTable( $tableName, $fName = __METHOD__ ) {
1364                 if ( !$this->tableExists( $tableName, $fName ) ) {
1365                         return false;
1366                 }
1367
1368                 // parent function incorrectly appends CASCADE, which we don't want
1369                 $sql = "DROP TABLE " . $this->tableName( $tableName );
1370
1371                 return $this->query( $sql, $fName );
1372         }
1373
1374         /**
1375          * Called in the installer and updater.
1376          * Probably doesn't need to be called anywhere else in the codebase.
1377          * @param bool|null $value
1378          * @return bool|null
1379          */
1380         public function prepareStatements( $value = null ) {
1381                 return wfSetVar( $this->mPrepareStatements, $value );
1382         }
1383
1384         /**
1385          * Called in the installer and updater.
1386          * Probably doesn't need to be called anywhere else in the codebase.
1387          * @param bool|null $value
1388          * @return bool|null
1389          */
1390         public function scrollableCursor( $value = null ) {
1391                 return wfSetVar( $this->mScrollableCursor, $value );
1392         }
1393
1394         /**
1395          * Called in the installer and updater.
1396          * Probably doesn't need to be called anywhere else in the codebase.
1397          * @param array|null $value
1398          * @return array|null
1399          */
1400         public function ignoreErrors( array $value = null ) {
1401                 return wfSetVar( $this->mIgnoreErrors, $value );
1402         }
1403 } // end DatabaseMssql class