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 realTimestamps() {
  58                 return false;
  59         }
  60
  61         public function implicitGroupby() {
  62                 return false;
  63         }
  64
  65         public function implicitOrderby() {
  66                 return false;
  67         }
  68
  69         public function functionalIndexes() {
  70                 return true;
  71         }
  72
  73         public function unionSupportsOrderAndLimit() {
  74                 return false;
  75         }
  76
  77         /**
  78          * Usually aborts on failure
  79          * @param string $server
  80          * @param string $user
  81          * @param string $password
  82          * @param string $dbName
  83          * @throws DBConnectionError
  84          * @return bool|resource|null
  85          */
  86         public function open( $server, $user, $password, $dbName ) {
  87                 # Test for driver support, to avoid suppressed fatal error
  88                 if ( !function_exists( 'sqlsrv_connect' ) ) {
  89                         throw new DBConnectionError(
  90                                 $this,
  91                                 "Microsoft SQL Server Native (sqlsrv) functions missing.
  92                                 You can download the driver from: http://go.microsoft.com/fwlink/?LinkId=123470\n"
  93                         );
  94                 }
  95
  96                 global $wgDBport, $wgDBWindowsAuthentication;
  97
  98                 # e.g. the class is being loaded
  99                 if ( !strlen( $user ) ) {
 100                         return null;
 101                 }
 102
 103                 $this->close();
 104                 $this->mServer = $server;
 105                 $this->mPort = $wgDBport;
 106                 $this->mUser = $user;
 107                 $this->mPassword = $password;
 108                 $this->mDBname = $dbName;
 109
 110                 $connectionInfo = [];
 111
 112                 if ( $dbName ) {
 113                         $connectionInfo['Database'] = $dbName;
 114                 }
 115
 116                 // Decide which auth scenerio to use
 117                 // if we are using Windows auth, don't add credentials to $connectionInfo
 118                 if ( !$wgDBWindowsAuthentication ) {
 119                         $connectionInfo['UID'] = $user;
 120                         $connectionInfo['PWD'] = $password;
 121                 }
 122
 123                 MediaWiki\suppressWarnings();
 124                 $this->mConn = sqlsrv_connect( $server, $connectionInfo );
 125                 MediaWiki\restoreWarnings();
 126
 127                 if ( $this->mConn === false ) {
 128                         throw new DBConnectionError( $this, $this->lastError() );
 129                 }
 130
 131                 $this->mOpened = true;
 132
 133                 return $this->mConn;
 134         }
 135
 136         /**
 137          * Closes a database connection, if it is open
 138          * Returns success, true if already closed
 139          * @return bool
 140          */
 141         protected function closeConnection() {
 142                 return sqlsrv_close( $this->mConn );
 143         }
 144
 145         /**
 146          * @param bool|MssqlResultWrapper|resource $result
 147          * @return bool|MssqlResultWrapper
 148          */
 149         protected function resultObject( $result ) {
 150                 if ( !$result ) {
 151                         return false;
 152                 } elseif ( $result instanceof MssqlResultWrapper ) {
 153                         return $result;
 154                 } elseif ( $result === true ) {
 155                         // Successful write query
 156                         return $result;
 157                 } else {
 158                         return new MssqlResultWrapper( $this, $result );
 159                 }
 160         }
 161
 162         /**
 163          * @param string $sql
 164          * @return bool|MssqlResult
 165          * @throws DBUnexpectedError
 166          */
 167         protected function doQuery( $sql ) {
 168                 if ( $this->getFlag( DBO_DEBUG ) ) {
 169                         wfDebug( "SQL: [$sql]\n" );
 170                 }
 171                 $this->offset = 0;
 172
 173                 // several extensions seem to think that all databases support limits
 174                 // via LIMIT N after the WHERE clause well, MSSQL uses SELECT TOP N,
 175                 // so to catch any of those extensions we'll do a quick check for a
 176                 // LIMIT clause and pass $sql through $this->LimitToTopN() which parses
 177                 // the limit clause and passes the result to $this->limitResult();
 178                 if ( preg_match( '/\bLIMIT\s*/i', $sql ) ) {
 179                         // massage LIMIT -> TopN
 180                         $sql = $this->LimitToTopN( $sql );
 181                 }
 182
 183                 // MSSQL doesn't have EXTRACT(epoch FROM XXX)
 184                 if ( preg_match( '#\bEXTRACT\s*?\(\s*?EPOCH\s+FROM\b#i', $sql, $matches ) ) {
 185                         // This is same as UNIX_TIMESTAMP, we need to calc # of seconds from 1970
 186                         $sql = str_replace( $matches[0], "DATEDIFF(s,CONVERT(datetime,'1/1/1970'),", $sql );
 187                 }
 188
 189                 // perform query
 190
 191                 // SQLSRV_CURSOR_STATIC is slower than SQLSRV_CURSOR_CLIENT_BUFFERED (one of the two is
 192                 // needed if we want to be able to seek around the result set), however CLIENT_BUFFERED
 193                 // has a bug in the sqlsrv driver where wchar_t types (such as nvarchar) that are empty
 194                 // strings make php throw a fatal error "Severe error translating Unicode"
 195                 if ( $this->mScrollableCursor ) {
 196                         $scrollArr = [ 'Scrollable' => SQLSRV_CURSOR_STATIC ];
 197                 } else {
 198                         $scrollArr = [];
 199                 }
 200
 201                 if ( $this->mPrepareStatements ) {
 202                         // we do prepare + execute so we can get its field metadata for later usage if desired
 203                         $stmt = sqlsrv_prepare( $this->mConn, $sql, [], $scrollArr );
 204                         $success = sqlsrv_execute( $stmt );
 205                 } else {
 206                         $stmt = sqlsrv_query( $this->mConn, $sql, [], $scrollArr );
 207                         $success = (bool)$stmt;
 208                 }
 209
 210                 // make a copy so that anything we add below does not get reflected in future queries
 211                 $ignoreErrors = $this->mIgnoreErrors;
 212
 213                 if ( $this->mIgnoreDupKeyErrors ) {
 214                         // ignore duplicate key errors
 215                         // this emulates INSERT IGNORE in MySQL
 216                         $ignoreErrors[] = '2601'; // duplicate key error caused by unique index
 217                         $ignoreErrors[] = '2627'; // duplicate key error caused by primary key
 218                         $ignoreErrors[] = '3621'; // generic "the statement has been terminated" error
 219                 }
 220
 221                 if ( $success === false ) {
 222                         $errors = sqlsrv_errors();
 223                         $success = true;
 224
 225                         foreach ( $errors as $err ) {
 226                                 if ( !in_array( $err['code'], $ignoreErrors ) ) {
 227                                         $success = false;
 228                                         break;
 229                                 }
 230                         }
 231
 232                         if ( $success === false ) {
 233                                 return false;
 234                         }
 235                 }
 236                 // remember number of rows affected
 237                 $this->mAffectedRows = sqlsrv_rows_affected( $stmt );
 238
 239                 return $stmt;
 240         }
 241
 242         public function freeResult( $res ) {
 243                 if ( $res instanceof ResultWrapper ) {
 244                         $res = $res->result;
 245                 }
 246
 247                 sqlsrv_free_stmt( $res );
 248         }
 249
 250         /**
 251          * @param MssqlResultWrapper $res
 252          * @return stdClass
 253          */
 254         public function fetchObject( $res ) {
 255                 // $res is expected to be an instance of MssqlResultWrapper here
 256                 return $res->fetchObject();
 257         }
 258
 259         /**
 260          * @param MssqlResultWrapper $res
 261          * @return array
 262          */
 263         public function fetchRow( $res ) {
 264                 return $res->fetchRow();
 265         }
 266
 267         /**
 268          * @param mixed $res
 269          * @return int
 270          */
 271         public function numRows( $res ) {
 272                 if ( $res instanceof ResultWrapper ) {
 273                         $res = $res->result;
 274                 }
 275
 276                 $ret = sqlsrv_num_rows( $res );
 277
 278                 if ( $ret === false ) {
 279                         // we cannot get an amount of rows from this cursor type
 280                         // has_rows returns bool true/false if the result has rows
 281                         $ret = (int)sqlsrv_has_rows( $res );
 282                 }
 283
 284                 return $ret;
 285         }
 286
 287         /**
 288          * @param mixed $res
 289          * @return int
 290          */
 291         public function numFields( $res ) {
 292                 if ( $res instanceof ResultWrapper ) {
 293                         $res = $res->result;
 294                 }
 295
 296                 return sqlsrv_num_fields( $res );
 297         }
 298
 299         /**
 300          * @param mixed $res
 301          * @param int $n
 302          * @return int
 303          */
 304         public function fieldName( $res, $n ) {
 305                 if ( $res instanceof ResultWrapper ) {
 306                         $res = $res->result;
 307                 }
 308
 309                 return sqlsrv_field_metadata( $res )[$n]['Name'];
 310         }
 311
 312         /**
 313          * This must be called after nextSequenceVal
 314          * @return int|null
 315          */
 316         public function insertId() {
 317                 return $this->mInsertId;
 318         }
 319
 320         /**
 321          * @param MssqlResultWrapper $res
 322          * @param int $row
 323          * @return bool
 324          */
 325         public function dataSeek( $res, $row ) {
 326                 return $res->seek( $row );
 327         }
 328
 329         /**
 330          * @return string
 331          */
 332         public function lastError() {
 333                 $strRet = '';
 334                 $retErrors = sqlsrv_errors( SQLSRV_ERR_ALL );
 335                 if ( $retErrors != null ) {
 336                         foreach ( $retErrors as $arrError ) {
 337                                 $strRet .= $this->formatError( $arrError ) . "\n";
 338                         }
 339                 } else {
 340                         $strRet = "No errors found";
 341                 }
 342
 343                 return $strRet;
 344         }
 345
 346         /**
 347          * @param array $err
 348          * @return string
 349          */
 350         private function formatError( $err ) {
 351                 return '[SQLSTATE ' . $err['SQLSTATE'] . '][Error Code ' . $err['code'] . ']' . $err['message'];
 352         }
 353
 354         /**
 355          * @return string
 356          */
 357         public function lastErrno() {
 358                 $err = sqlsrv_errors( SQLSRV_ERR_ALL );
 359                 if ( $err !== null && isset( $err[0] ) ) {
 360                         return $err[0]['code'];
 361                 } else {
 362                         return 0;
 363                 }
 364         }
 365
 366         /**
 367          * @return int
 368          */
 369         public function affectedRows() {
 370                 return $this->mAffectedRows;
 371         }
 372
 373         /**
 374          * SELECT wrapper
 375          *
 376          * @param mixed $table Array or string, table name(s) (prefix auto-added)
 377          * @param mixed $vars Array or string, field name(s) to be retrieved
 378          * @param mixed $conds Array or string, condition(s) for WHERE
 379          * @param string $fname Calling function name (use __METHOD__) for logs/profiling
 380          * @param array $options Associative array of options (e.g.
 381          *   [ 'GROUP BY' => 'page_title' ]), see Database::makeSelectOptions
 382          *   code for list of supported stuff
 383          * @param array $join_conds Associative array of table join conditions
 384          *   (optional) (e.g. [ 'page' => [ 'LEFT JOIN','page_latest=rev_id' ] ]
 385          * @return mixed Database result resource (feed to Database::fetchObject
 386          *   or whatever), or false on failure
 387          * @throws DBQueryError
 388          * @throws DBUnexpectedError
 389          * @throws Exception
 390          */
 391         public function select( $table, $vars, $conds = '', $fname = __METHOD__,
 392                 $options = [], $join_conds = []
 393         ) {
 394                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 395                 if ( isset( $options['EXPLAIN'] ) ) {
 396                         try {
 397                                 $this->mScrollableCursor = false;
 398                                 $this->mPrepareStatements = false;
 399                                 $this->query( "SET SHOWPLAN_ALL ON" );
 400                                 $ret = $this->query( $sql, $fname );
 401                                 $this->query( "SET SHOWPLAN_ALL OFF" );
 402                         } catch ( DBQueryError $dqe ) {
 403                                 if ( isset( $options['FOR COUNT'] ) ) {
 404                                         // likely don't have privs for SHOWPLAN, so run a select count instead
 405                                         $this->query( "SET SHOWPLAN_ALL OFF" );
 406                                         unset( $options['EXPLAIN'] );
 407                                         $ret = $this->select(
 408                                                 $table,
 409                                                 'COUNT(*) AS EstimateRows',
 410                                                 $conds,
 411                                                 $fname,
 412                                                 $options,
 413                                                 $join_conds
 414                                         );
 415                                 } else {
 416                                         // someone actually wanted the query plan instead of an est row count
 417                                         // let them know of the error
 418                                         $this->mScrollableCursor = true;
 419                                         $this->mPrepareStatements = true;
 420                                         throw $dqe;
 421                                 }
 422                         }
 423                         $this->mScrollableCursor = true;
 424                         $this->mPrepareStatements = true;
 425                         return $ret;
 426                 }
 427                 return $this->query( $sql, $fname );
 428         }
 429
 430         /**
 431          * SELECT wrapper
 432          *
 433          * @param mixed $table Array or string, table name(s) (prefix auto-added)
 434          * @param mixed $vars Array or string, field name(s) to be retrieved
 435          * @param mixed $conds Array or string, condition(s) for WHERE
 436          * @param string $fname Calling function name (use __METHOD__) for logs/profiling
 437          * @param array $options Associative array of options (e.g. [ 'GROUP BY' => 'page_title' ]),
 438          *   see Database::makeSelectOptions code for list of supported stuff
 439          * @param array $join_conds Associative array of table join conditions (optional)
 440          *    (e.g. [ 'page' => [ 'LEFT JOIN','page_latest=rev_id' ] ]
 441          * @return string The SQL text
 442          */
 443         public function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 444                 $options = [], $join_conds = []
 445         ) {
 446                 if ( isset( $options['EXPLAIN'] ) ) {
 447                         unset( $options['EXPLAIN'] );
 448                 }
 449
 450                 $sql = parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 451
 452                 // try to rewrite aggregations of bit columns (currently MAX and MIN)
 453                 if ( strpos( $sql, 'MAX(' ) !== false || strpos( $sql, 'MIN(' ) !== false ) {
 454                         $bitColumns = [];
 455                         if ( is_array( $table ) ) {
 456                                 foreach ( $table as $t ) {
 457                                         $bitColumns += $this->getBitColumns( $this->tableName( $t ) );
 458                                 }
 459                         } else {
 460                                 $bitColumns = $this->getBitColumns( $this->tableName( $table ) );
 461                         }
 462
 463                         foreach ( $bitColumns as $col => $info ) {
 464                                 $replace = [
 465                                         "MAX({$col})" => "MAX(CAST({$col} AS tinyint))",
 466                                         "MIN({$col})" => "MIN(CAST({$col} AS tinyint))",
 467                                 ];
 468                                 $sql = str_replace( array_keys( $replace ), array_values( $replace ), $sql );
 469                         }
 470                 }
 471
 472                 return $sql;
 473         }
 474
 475         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
 476                 $fname = __METHOD__
 477         ) {
 478                 $this->mScrollableCursor = false;
 479                 try {
 480                         parent::deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname );
 481                 } catch ( Exception $e ) {
 482                         $this->mScrollableCursor = true;
 483                         throw $e;
 484                 }
 485                 $this->mScrollableCursor = true;
 486         }
 487
 488         public function delete( $table, $conds, $fname = __METHOD__ ) {
 489                 $this->mScrollableCursor = false;
 490                 try {
 491                         parent::delete( $table, $conds, $fname );
 492                 } catch ( Exception $e ) {
 493                         $this->mScrollableCursor = true;
 494                         throw $e;
 495                 }
 496                 $this->mScrollableCursor = true;
 497         }
 498
 499         /**
 500          * Estimate rows in dataset
 501          * Returns estimated count, based on SHOWPLAN_ALL output
 502          * This is not necessarily an accurate estimate, so use sparingly
 503          * Returns -1 if count cannot be found
 504          * Takes same arguments as Database::select()
 505          * @param string $table
 506          * @param string $vars
 507          * @param string $conds
 508          * @param string $fname
 509          * @param array $options
 510          * @return int
 511          */
 512         public function estimateRowCount( $table, $vars = '*', $conds = '',
 513                 $fname = __METHOD__, $options = []
 514         ) {
 515                 // http://msdn2.microsoft.com/en-us/library/aa259203.aspx
 516                 $options['EXPLAIN'] = true;
 517                 $options['FOR COUNT'] = true;
 518                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 519
 520                 $rows = -1;
 521                 if ( $res ) {
 522                         $row = $this->fetchRow( $res );
 523
 524                         if ( isset( $row['EstimateRows'] ) ) {
 525                                 $rows = (int)$row['EstimateRows'];
 526                         }
 527                 }
 528
 529                 return $rows;
 530         }
 531
 532         /**
 533          * Returns information about an index
 534          * If errors are explicitly ignored, returns NULL on failure
 535          * @param string $table
 536          * @param string $index
 537          * @param string $fname
 538          * @return array|bool|null
 539          */
 540         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 541                 # This does not return the same info as MYSQL would, but that's OK
 542                 # because MediaWiki never uses the returned value except to check for
 543                 # the existance of indexes.
 544                 $sql = "sp_helpindex '" . $this->tableName( $table ) . "'";
 545                 $res = $this->query( $sql, $fname );
 546
 547                 if ( !$res ) {
 548                         return null;
 549                 }
 550
 551                 $result = [];
 552                 foreach ( $res as $row ) {
 553                         if ( $row->index_name == $index ) {
 554                                 $row->Non_unique = !stristr( $row->index_description, "unique" );
 555                                 $cols = explode( ", ", $row->index_keys );
 556                                 foreach ( $cols as $col ) {
 557                                         $row->Column_name = trim( $col );
 558                                         $result[] = clone $row;
 559                                 }
 560                         } elseif ( $index == 'PRIMARY' && stristr( $row->index_description, 'PRIMARY' ) ) {
 561                                 $row->Non_unique = 0;
 562                                 $cols = explode( ", ", $row->index_keys );
 563                                 foreach ( $cols as $col ) {
 564                                         $row->Column_name = trim( $col );
 565                                         $result[] = clone $row;
 566                                 }
 567                         }
 568                 }
 569
 570                 return empty( $result ) ? false : $result;
 571         }
 572
 573         /**
 574          * INSERT wrapper, inserts an array into a table
 575          *
 576          * $arrToInsert may be a single associative array, or an array of these with numeric keys, for
 577          * multi-row insert.
 578          *
 579          * Usually aborts on failure
 580          * If errors are explicitly ignored, returns success
 581          * @param string $table
 582          * @param array $arrToInsert
 583          * @param string $fname
 584          * @param array $options
 585          * @return bool
 586          * @throws Exception
 587          */
 588         public function insert( $table, $arrToInsert, $fname = __METHOD__, $options = [] ) {
 589                 # No rows to insert, easy just return now
 590                 if ( !count( $arrToInsert ) ) {
 591                         return true;
 592                 }
 593
 594                 if ( !is_array( $options ) ) {
 595                         $options = [ $options ];
 596                 }
 597
 598                 $table = $this->tableName( $table );
 599
 600                 if ( !( isset( $arrToInsert[0] ) && is_array( $arrToInsert[0] ) ) ) { // Not multi row
 601                         $arrToInsert = [ 0 => $arrToInsert ]; // make everything multi row compatible
 602                 }
 603
 604                 // We know the table we're inserting into, get its identity column
 605                 $identity = null;
 606                 // strip matching square brackets and the db/schema from table name
 607                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
 608                 $tableRaw = array_pop( $tableRawArr );
 609                 $res = $this->doQuery(
 610                         "SELECT NAME AS idColumn FROM SYS.IDENTITY_COLUMNS " .
 611                                 "WHERE OBJECT_NAME(OBJECT_ID)='{$tableRaw}'"
 612                 );
 613                 if ( $res && sqlsrv_has_rows( $res ) ) {
 614                         // There is an identity for this table.
 615                         $identityArr = sqlsrv_fetch_array( $res, SQLSRV_FETCH_ASSOC );
 616                         $identity = array_pop( $identityArr );
 617                 }
 618                 sqlsrv_free_stmt( $res );
 619
 620                 // Determine binary/varbinary fields so we can encode data as a hex string like 0xABCDEF
 621                 $binaryColumns = $this->getBinaryColumns( $table );
 622
 623                 // INSERT IGNORE is not supported by SQL Server
 624                 // remove IGNORE from options list and set ignore flag to true
 625                 if ( in_array( 'IGNORE', $options ) ) {
 626                         $options = array_diff( $options, [ 'IGNORE' ] );
 627                         $this->mIgnoreDupKeyErrors = true;
 628                 }
 629
 630                 foreach ( $arrToInsert as $a ) {
 631                         // start out with empty identity column, this is so we can return
 632                         // it as a result of the insert logic
 633                         $sqlPre = '';
 634                         $sqlPost = '';
 635                         $identityClause = '';
 636
 637                         // if we have an identity column
 638                         if ( $identity ) {
 639                                 // iterate through
 640                                 foreach ( $a as $k => $v ) {
 641                                         if ( $k == $identity ) {
 642                                                 if ( !is_null( $v ) ) {
 643                                                         // there is a value being passed to us,
 644                                                         // we need to turn on and off inserted identity
 645                                                         $sqlPre = "SET IDENTITY_INSERT $table ON;";
 646                                                         $sqlPost = ";SET IDENTITY_INSERT $table OFF;";
 647                                                 } else {
 648                                                         // we can't insert NULL into an identity column,
 649                                                         // so remove the column from the insert.
 650                                                         unset( $a[$k] );
 651                                                 }
 652                                         }
 653                                 }
 654
 655                                 // we want to output an identity column as result
 656                                 $identityClause = "OUTPUT INSERTED.$identity ";
 657                         }
 658
 659                         $keys = array_keys( $a );
 660
 661                         // Build the actual query
 662                         $sql = $sqlPre . 'INSERT ' . implode( ' ', $options ) .
 663                                 " INTO $table (" . implode( ',', $keys ) . ") $identityClause VALUES (";
 664
 665                         $first = true;
 666                         foreach ( $a as $key => $value ) {
 667                                 if ( isset( $binaryColumns[$key] ) ) {
 668                                         $value = new MssqlBlob( $value );
 669                                 }
 670                                 if ( $first ) {
 671                                         $first = false;
 672                                 } else {
 673                                         $sql .= ',';
 674                                 }
 675                                 if ( is_null( $value ) ) {
 676                                         $sql .= 'null';
 677                                 } elseif ( is_array( $value ) || is_object( $value ) ) {
 678                                         if ( is_object( $value ) && $value instanceof Blob ) {
 679                                                 $sql .= $this->addQuotes( $value );
 680                                         } else {
 681                                                 $sql .= $this->addQuotes( serialize( $value ) );
 682                                         }
 683                                 } else {
 684                                         $sql .= $this->addQuotes( $value );
 685                                 }
 686                         }
 687                         $sql .= ')' . $sqlPost;
 688
 689                         // Run the query
 690                         $this->mScrollableCursor = false;
 691                         try {
 692                                 $ret = $this->query( $sql );
 693                         } catch ( Exception $e ) {
 694                                 $this->mScrollableCursor = true;
 695                                 $this->mIgnoreDupKeyErrors = false;
 696                                 throw $e;
 697                         }
 698                         $this->mScrollableCursor = true;
 699
 700                         if ( !is_null( $identity ) ) {
 701                                 // then we want to get the identity column value we were assigned and save it off
 702                                 $row = $ret->fetchObject();
 703                                 if ( is_object( $row ) ) {
 704                                         $this->mInsertId = $row->$identity;
 705
 706                                         // it seems that mAffectedRows is -1 sometimes when OUTPUT INSERTED.identity is used
 707                                         // if we got an identity back, we know for sure a row was affected, so adjust that here
 708                                         if ( $this->mAffectedRows == -1 ) {
 709                                                 $this->mAffectedRows = 1;
 710                                         }
 711                                 }
 712                         }
 713                 }
 714                 $this->mIgnoreDupKeyErrors = false;
 715                 return $ret;
 716         }
 717
 718         /**
 719          * INSERT SELECT wrapper
 720          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 721          * Source items may be literals rather than field names, but strings should
 722          * be quoted with Database::addQuotes().
 723          * @param string $destTable
 724          * @param array|string $srcTable May be an array of tables.
 725          * @param array $varMap
 726          * @param array $conds May be "*" to copy the whole table.
 727          * @param string $fname
 728          * @param array $insertOptions
 729          * @param array $selectOptions
 730          * @return null|ResultWrapper
 731          * @throws Exception
 732          */
 733         public function nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 734                 $insertOptions = [], $selectOptions = []
 735         ) {
 736                 $this->mScrollableCursor = false;
 737                 try {
 738                         $ret = parent::nativeInsertSelect(
 739                                 $destTable,
 740                                 $srcTable,
 741                                 $varMap,
 742                                 $conds,
 743                                 $fname,
 744                                 $insertOptions,
 745                                 $selectOptions
 746                         );
 747                 } catch ( Exception $e ) {
 748                         $this->mScrollableCursor = true;
 749                         throw $e;
 750                 }
 751                 $this->mScrollableCursor = true;
 752
 753                 return $ret;
 754         }
 755
 756         /**
 757          * UPDATE wrapper. Takes a condition array and a SET array.
 758          *
 759          * @param string $table Name of the table to UPDATE. This will be passed through
 760          *                DatabaseBase::tableName().
 761          *
 762          * @param array $values An array of values to SET. For each array element,
 763          *                the key gives the field name, and the value gives the data
 764          *                to set that field to. The data will be quoted by
 765          *                DatabaseBase::addQuotes().
 766          *
 767          * @param array $conds An array of conditions (WHERE). See
 768          *                DatabaseBase::select() for the details of the format of
 769          *                condition arrays. Use '*' to update all rows.
 770          *
 771          * @param string $fname The function name of the caller (from __METHOD__),
 772          *                for logging and profiling.
 773          *
 774          * @param array $options An array of UPDATE options, can be:
 775          *                   - IGNORE: Ignore unique key conflicts
 776          *                   - LOW_PRIORITY: MySQL-specific, see MySQL manual.
 777          * @return bool
 778          * @throws DBUnexpectedError
 779          * @throws Exception
 780          */
 781         function update( $table, $values, $conds, $fname = __METHOD__, $options = [] ) {
 782                 $table = $this->tableName( $table );
 783                 $binaryColumns = $this->getBinaryColumns( $table );
 784
 785                 $opts = $this->makeUpdateOptions( $options );
 786                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET, $binaryColumns );
 787
 788                 if ( $conds !== [] && $conds !== '*' ) {
 789                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND, $binaryColumns );
 790                 }
 791
 792                 $this->mScrollableCursor = false;
 793                 try {
 794                         $ret = $this->query( $sql );
 795                 } catch ( Exception $e ) {
 796                         $this->mScrollableCursor = true;
 797                         throw $e;
 798                 }
 799                 $this->mScrollableCursor = true;
 800                 return true;
 801         }
 802
 803         /**
 804          * Makes an encoded list of strings from an array
 805          * @param array $a Containing the data
 806          * @param int $mode Constant
 807          *      - LIST_COMMA:          comma separated, no field names
 808          *      - LIST_AND:            ANDed WHERE clause (without the WHERE). See
 809          *        the documentation for $conds in DatabaseBase::select().
 810          *      - LIST_OR:             ORed WHERE clause (without the WHERE)
 811          *      - LIST_SET:            comma separated with field names, like a SET clause
 812          *      - LIST_NAMES:          comma separated field names
 813          * @param array $binaryColumns Contains a list of column names that are binary types
 814          *      This is a custom parameter only present for MS SQL.
 815          *
 816          * @throws DBUnexpectedError
 817          * @return string
 818          */
 819         public function makeList( $a, $mode = LIST_COMMA, $binaryColumns = [] ) {
 820                 if ( !is_array( $a ) ) {
 821                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with incorrect parameters' );
 822                 }
 823
 824                 if ( $mode != LIST_NAMES ) {
 825                         // In MS SQL, values need to be specially encoded when they are
 826                         // inserted into binary fields. Perform this necessary encoding
 827                         // for the specified set of columns.
 828                         foreach ( array_keys( $a ) as $field ) {
 829                                 if ( !isset( $binaryColumns[$field] ) ) {
 830                                         continue;
 831                                 }
 832
 833                                 if ( is_array( $a[$field] ) ) {
 834                                         foreach ( $a[$field] as &$v ) {
 835                                                 $v = new MssqlBlob( $v );
 836                                         }
 837                                         unset( $v );
 838                                 } else {
 839                                         $a[$field] = new MssqlBlob( $a[$field] );
 840                                 }
 841                         }
 842                 }
 843
 844                 return parent::makeList( $a, $mode );
 845         }
 846
 847         /**
 848          * @param string $table
 849          * @param string $field
 850          * @return int Returns the size of a text field, or -1 for "unlimited"
 851          */
 852         public function textFieldSize( $table, $field ) {
 853                 $table = $this->tableName( $table );
 854                 $sql = "SELECT CHARACTER_MAXIMUM_LENGTH,DATA_TYPE FROM INFORMATION_SCHEMA.Columns
 855                         WHERE TABLE_NAME = '$table' AND COLUMN_NAME = '$field'";
 856                 $res = $this->query( $sql );
 857                 $row = $this->fetchRow( $res );
 858                 $size = -1;
 859                 if ( strtolower( $row['DATA_TYPE'] ) != 'text' ) {
 860                         $size = $row['CHARACTER_MAXIMUM_LENGTH'];
 861                 }
 862
 863                 return $size;
 864         }
 865
 866         /**
 867          * Construct a LIMIT query with optional offset
 868          * This is used for query pages
 869          *
 870          * @param string $sql SQL query we will append the limit too
 871          * @param int $limit The SQL limit
 872          * @param bool|int $offset The SQL offset (default false)
 873          * @return array|string
 874          * @throws DBUnexpectedError
 875          */
 876         public function limitResult( $sql, $limit, $offset = false ) {
 877                 if ( $offset === false || $offset == 0 ) {
 878                         if ( strpos( $sql, "SELECT" ) === false ) {
 879                                 return "TOP {$limit} " . $sql;
 880                         } else {
 881                                 return preg_replace( '/\bSELECT(\s+DISTINCT)?\b/Dsi',
 882                                         'SELECT$1 TOP ' . $limit, $sql, 1 );
 883                         }
 884                 } else {
 885                         // This one is fun, we need to pull out the select list as well as any ORDER BY clause
 886                         $select = $orderby = [];
 887                         $s1 = preg_match( '#SELECT\s+(.+?)\s+FROM#Dis', $sql, $select );
 888                         $s2 = preg_match( '#(ORDER BY\s+.+?)(\s*FOR XML .*)?$#Dis', $sql, $orderby );
 889                         $overOrder = $postOrder = '';
 890                         $first = $offset + 1;
 891                         $last = $offset + $limit;
 892                         $sub1 = 'sub_' . $this->mSubqueryId;
 893                         $sub2 = 'sub_' . ( $this->mSubqueryId + 1 );
 894                         $this->mSubqueryId += 2;
 895                         if ( !$s1 ) {
 896                                 // wat
 897                                 throw new DBUnexpectedError( $this, "Attempting to LIMIT a non-SELECT query\n" );
 898                         }
 899                         if ( !$s2 ) {
 900                                 // no ORDER BY
 901                                 $overOrder = 'ORDER BY (SELECT 1)';
 902                         } else {
 903                                 if ( !isset( $orderby[2] ) || !$orderby[2] ) {
 904                                         // don't need to strip it out if we're using a FOR XML clause
 905                                         $sql = str_replace( $orderby[1], '', $sql );
 906                                 }
 907                                 $overOrder = $orderby[1];
 908                                 $postOrder = ' ' . $overOrder;
 909                         }
 910                         $sql = "SELECT {$select[1]}
 911                                         FROM (
 912                                                 SELECT ROW_NUMBER() OVER({$overOrder}) AS rowNumber, *
 913                                                 FROM ({$sql}) {$sub1}
 914                                         ) {$sub2}
 915                                         WHERE rowNumber BETWEEN {$first} AND {$last}{$postOrder}";
 916
 917                         return $sql;
 918                 }
 919         }
 920
 921         /**
 922          * If there is a limit clause, parse it, strip it, and pass the remaining
 923          * SQL through limitResult() with the appropriate parameters. Not the
 924          * prettiest solution, but better than building a whole new parser. This
 925          * exists becase there are still too many extensions that don't use dynamic
 926          * sql generation.
 927          *
 928          * @param string $sql
 929          * @return array|mixed|string
 930          */
 931         public function LimitToTopN( $sql ) {
 932                 // Matches: LIMIT {[offset,] row_count | row_count OFFSET offset}
 933                 $pattern = '/\bLIMIT\s+((([0-9]+)\s*,\s*)?([0-9]+)(\s+OFFSET\s+([0-9]+))?)/i';
 934                 if ( preg_match( $pattern, $sql, $matches ) ) {
 935                         $row_count = $matches[4];
 936                         $offset = $matches[3] ?: $matches[6] ?: false;
 937
 938                         // strip the matching LIMIT clause out
 939                         $sql = str_replace( $matches[0], '', $sql );
 940
 941                         return $this->limitResult( $sql, $row_count, $offset );
 942                 }
 943
 944                 return $sql;
 945         }
 946
 947         /**
 948          * @return string Wikitext of a link to the server software's web site
 949          */
 950         public function getSoftwareLink() {
 951                 return "[{{int:version-db-mssql-url}} MS SQL Server]";
 952         }
 953
 954         /**
 955          * @return string Version information from the database
 956          */
 957         public function getServerVersion() {
 958                 $server_info = sqlsrv_server_info( $this->mConn );
 959                 $version = 'Error';
 960                 if ( isset( $server_info['SQLServerVersion'] ) ) {
 961                         $version = $server_info['SQLServerVersion'];
 962                 }
 963
 964                 return $version;
 965         }
 966
 967         /**
 968          * @param string $table
 969          * @param string $fname
 970          * @return bool
 971          */
 972         public function tableExists( $table, $fname = __METHOD__ ) {
 973                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
 974
 975                 if ( $db !== false ) {
 976                         // remote database
 977                         wfDebug( "Attempting to call tableExists on a remote table" );
 978                         return false;
 979                 }
 980
 981                 if ( $schema === false ) {
 982                         global $wgDBmwschema;
 983                         $schema = $wgDBmwschema;
 984                 }
 985
 986                 $res = $this->query( "SELECT 1 FROM INFORMATION_SCHEMA.TABLES
 987                         WHERE TABLE_TYPE = 'BASE TABLE'
 988                         AND TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table'" );
 989
 990                 if ( $res->numRows() ) {
 991                         return true;
 992                 } else {
 993                         return false;
 994                 }
 995         }
 996
 997         /**
 998          * Query whether a given column exists in the mediawiki schema
 999          * @param string $table
1000          * @param string $field
1001          * @param string $fname
1002          * @return bool
1003          */
1004         public function fieldExists( $table, $field, $fname = __METHOD__ ) {
1005                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
1006
1007                 if ( $db !== false ) {
1008                         // remote database
1009                         wfDebug( "Attempting to call fieldExists on a remote table" );
1010                         return false;
1011                 }
1012
1013                 $res = $this->query( "SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS
1014                         WHERE TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table' AND COLUMN_NAME = '$field'" );
1015
1016                 if ( $res->numRows() ) {
1017                         return true;
1018                 } else {
1019                         return false;
1020                 }
1021         }
1022
1023         public function fieldInfo( $table, $field ) {
1024                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
1025
1026                 if ( $db !== false ) {
1027                         // remote database
1028                         wfDebug( "Attempting to call fieldInfo on a remote table" );
1029                         return false;
1030                 }
1031
1032                 $res = $this->query( "SELECT * FROM INFORMATION_SCHEMA.COLUMNS
1033                         WHERE TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table' AND COLUMN_NAME = '$field'" );
1034
1035                 $meta = $res->fetchRow();
1036                 if ( $meta ) {
1037                         return new MssqlField( $meta );
1038                 }
1039
1040                 return false;
1041         }
1042
1043         /**
1044          * Begin a transaction, committing any previously open transaction
1045          * @param string $fname
1046          */
1047         protected function doBegin( $fname = __METHOD__ ) {
1048                 sqlsrv_begin_transaction( $this->mConn );
1049                 $this->mTrxLevel = 1;
1050         }
1051
1052         /**
1053          * End a transaction
1054          * @param string $fname
1055          */
1056         protected function doCommit( $fname = __METHOD__ ) {
1057                 sqlsrv_commit( $this->mConn );
1058                 $this->mTrxLevel = 0;
1059         }
1060
1061         /**
1062          * Rollback a transaction.
1063          * No-op on non-transactional databases.
1064          * @param string $fname
1065          */
1066         protected function doRollback( $fname = __METHOD__ ) {
1067                 sqlsrv_rollback( $this->mConn );
1068                 $this->mTrxLevel = 0;
1069         }
1070
1071         /**
1072          * Escapes a identifier for use inm SQL.
1073          * Throws an exception if it is invalid.
1074          * Reference: http://msdn.microsoft.com/en-us/library/aa224033%28v=SQL.80%29.aspx
1075          * @param string $identifier
1076          * @throws InvalidArgumentException
1077          * @return string
1078          */
1079         private function escapeIdentifier( $identifier ) {
1080                 if ( strlen( $identifier ) == 0 ) {
1081                         throw new InvalidArgumentException( "An identifier must not be empty" );
1082                 }
1083                 if ( strlen( $identifier ) > 128 ) {
1084                         throw new InvalidArgumentException( "The identifier '$identifier' is too long (max. 128)" );
1085                 }
1086                 if ( ( strpos( $identifier, '[' ) !== false )
1087                         || ( strpos( $identifier, ']' ) !== false )
1088                 ) {
1089                         // It may be allowed if you quoted with double quotation marks, but
1090                         // that would break if QUOTED_IDENTIFIER is OFF
1091                         throw new InvalidArgumentException( "Square brackets are not allowed in '$identifier'" );
1092                 }
1093
1094                 return "[$identifier]";
1095         }
1096
1097         /**
1098          * @param string $s
1099          * @return string
1100          */
1101         public function strencode( $s ) {
1102                 // Should not be called by us
1103
1104                 return str_replace( "'", "''", $s );
1105         }
1106
1107         /**
1108          * @param string|Blob $s
1109          * @return string
1110          */
1111         public function addQuotes( $s ) {
1112                 if ( $s instanceof MssqlBlob ) {
1113                         return $s->fetch();
1114                 } elseif ( $s instanceof Blob ) {
1115                         // this shouldn't really ever be called, but it's here if needed
1116                         // (and will quite possibly make the SQL error out)
1117                         $blob = new MssqlBlob( $s->fetch() );
1118                         return $blob->fetch();
1119                 } else {
1120                         if ( is_bool( $s ) ) {
1121                                 $s = $s ? 1 : 0;
1122                         }
1123                         return parent::addQuotes( $s );
1124                 }
1125         }
1126
1127         /**
1128          * @param string $s
1129          * @return string
1130          */
1131         public function addIdentifierQuotes( $s ) {
1132                 // http://msdn.microsoft.com/en-us/library/aa223962.aspx
1133                 return '[' . $s . ']';
1134         }
1135
1136         /**
1137          * @param string $name
1138          * @return bool
1139          */
1140         public function isQuotedIdentifier( $name ) {
1141                 return strlen( $name ) && $name[0] == '[' && substr( $name, -1, 1 ) == ']';
1142         }
1143
1144         /**
1145          * MS SQL supports more pattern operators than other databases (ex: [,],^)
1146          *
1147          * @param string $s
1148          * @return string
1149          */
1150         protected function escapeLikeInternal( $s ) {
1151                 return addcslashes( $s, '\%_[]^' );
1152         }
1153
1154         /**
1155          * MS SQL requires specifying the escape character used in a LIKE query
1156          * or using Square brackets to surround characters that are to be escaped
1157          * http://msdn.microsoft.com/en-us/library/ms179859.aspx
1158          * Here we take the Specify-Escape-Character approach since it's less
1159          * invasive, renders a query that is closer to other DB's and better at
1160          * handling square bracket escaping
1161          *
1162          * @return string Fully built LIKE statement
1163          */
1164         public function buildLike() {
1165                 $params = func_get_args();
1166                 if ( count( $params ) > 0 && is_array( $params[0] ) ) {
1167                         $params = $params[0];
1168                 }
1169
1170                 return parent::buildLike( $params ) . " ESCAPE '\' ";
1171         }
1172
1173         /**
1174          * @param string $db
1175          * @return bool
1176          */
1177         public function selectDB( $db ) {
1178                 try {
1179                         $this->mDBname = $db;
1180                         $this->query( "USE $db" );
1181                         return true;
1182                 } catch ( Exception $e ) {
1183                         return false;
1184                 }
1185         }
1186
1187         /**
1188          * @param array $options An associative array of options to be turned into
1189          *   an SQL query, valid keys are listed in the function.
1190          * @return array
1191          */
1192         public function makeSelectOptions( $options ) {
1193                 $tailOpts = '';
1194                 $startOpts = '';
1195
1196                 $noKeyOptions = [];
1197                 foreach ( $options as $key => $option ) {
1198                         if ( is_numeric( $key ) ) {
1199                                 $noKeyOptions[$option] = true;
1200                         }
1201                 }
1202
1203                 $tailOpts .= $this->makeGroupByWithHaving( $options );
1204
1205                 $tailOpts .= $this->makeOrderBy( $options );
1206
1207                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1208                         $startOpts .= 'DISTINCT';
1209                 }
1210
1211                 if ( isset( $noKeyOptions['FOR XML'] ) ) {
1212                         // used in group concat field emulation
1213                         $tailOpts .= " FOR XML PATH('')";
1214                 }
1215
1216                 // we want this to be compatible with the output of parent::makeSelectOptions()
1217                 return [ $startOpts, '', $tailOpts, '', '' ];
1218         }
1219
1220         /**
1221          * Get the type of the DBMS, as it appears in $wgDBtype.
1222          * @return string
1223          */
1224         public function getType() {
1225                 return 'mssql';
1226         }
1227
1228         /**
1229          * @param array $stringList
1230          * @return string
1231          */
1232         public function buildConcat( $stringList ) {
1233                 return implode( ' + ', $stringList );
1234         }
1235
1236         /**
1237          * Build a GROUP_CONCAT or equivalent statement for a query.
1238          * MS SQL doesn't have GROUP_CONCAT so we emulate it with other stuff (and boy is it nasty)
1239          *
1240          * This is useful for combining a field for several rows into a single string.
1241          * NULL values will not appear in the output, duplicated values will appear,
1242          * and the resulting delimiter-separated values have no defined sort order.
1243          * Code using the results may need to use the PHP unique() or sort() methods.
1244          *
1245          * @param string $delim Glue to bind the results together
1246          * @param string|array $table Table name
1247          * @param string $field Field name
1248          * @param string|array $conds Conditions
1249          * @param string|array $join_conds Join conditions
1250          * @return string SQL text
1251          * @since 1.23
1252          */
1253         public function buildGroupConcatField( $delim, $table, $field, $conds = '',
1254                 $join_conds = []
1255         ) {
1256                 $gcsq = 'gcsq_' . $this->mSubqueryId;
1257                 $this->mSubqueryId++;
1258
1259                 $delimLen = strlen( $delim );
1260                 $fld = "{$field} + {$this->addQuotes( $delim )}";
1261                 $sql = "(SELECT LEFT({$field}, LEN({$field}) - {$delimLen}) FROM ("
1262                         . $this->selectSQLText( $table, $fld, $conds, null, [ 'FOR XML' ], $join_conds )
1263                         . ") {$gcsq} ({$field}))";
1264
1265                 return $sql;
1266         }
1267
1268         /**
1269          * @return string
1270          */
1271         public function getSearchEngine() {
1272                 return "SearchMssql";
1273         }
1274
1275         /**
1276          * Returns an associative array for fields that are of type varbinary, binary, or image
1277          * $table can be either a raw table name or passed through tableName() first
1278          * @param string $table
1279          * @return array
1280          */
1281         private function getBinaryColumns( $table ) {
1282                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
1283                 $tableRaw = array_pop( $tableRawArr );
1284
1285                 if ( $this->mBinaryColumnCache === null ) {
1286                         $this->populateColumnCaches();
1287                 }
1288
1289                 return isset( $this->mBinaryColumnCache[$tableRaw] )
1290                         ? $this->mBinaryColumnCache[$tableRaw]
1291                         : [];
1292         }
1293
1294         /**
1295          * @param string $table
1296          * @return array
1297          */
1298         private function getBitColumns( $table ) {
1299                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
1300                 $tableRaw = array_pop( $tableRawArr );
1301
1302                 if ( $this->mBitColumnCache === null ) {
1303                         $this->populateColumnCaches();
1304                 }
1305
1306                 return isset( $this->mBitColumnCache[$tableRaw] )
1307                         ? $this->mBitColumnCache[$tableRaw]
1308                         : [];
1309         }
1310
1311         private function populateColumnCaches() {
1312                 $res = $this->select( 'INFORMATION_SCHEMA.COLUMNS', '*',
1313                         [
1314                                 'TABLE_CATALOG' => $this->mDBname,
1315                                 'TABLE_SCHEMA' => $this->mSchema,
1316                                 'DATA_TYPE' => [ 'varbinary', 'binary', 'image', 'bit' ]
1317                         ] );
1318
1319                 $this->mBinaryColumnCache = [];
1320                 $this->mBitColumnCache = [];
1321                 foreach ( $res as $row ) {
1322                         if ( $row->DATA_TYPE == 'bit' ) {
1323                                 $this->mBitColumnCache[$row->TABLE_NAME][$row->COLUMN_NAME] = $row;
1324                         } else {
1325                                 $this->mBinaryColumnCache[$row->TABLE_NAME][$row->COLUMN_NAME] = $row;
1326                         }
1327                 }
1328         }
1329
1330         /**
1331          * @param string $name
1332          * @param string $format
1333          * @return string
1334          */
1335         function tableName( $name, $format = 'quoted' ) {
1336                 # Replace reserved words with better ones
1337                 switch ( $name ) {
1338                         case 'user':
1339                                 return $this->realTableName( 'mwuser', $format );
1340                         default:
1341                                 return $this->realTableName( $name, $format );
1342                 }
1343         }
1344
1345         /**
1346          * call this instead of tableName() in the updater when renaming tables
1347          * @param string $name
1348          * @param string $format One of quoted, raw, or split
1349          * @return string
1350          */
1351         function realTableName( $name, $format = 'quoted' ) {
1352                 $table = parent::tableName( $name, $format );
1353                 if ( $format == 'split' ) {
1354                         // Used internally, we want the schema split off from the table name and returned
1355                         // as a list with 3 elements (database, schema, table)
1356                         $table = explode( '.', $table );
1357                         while ( count( $table ) < 3 ) {
1358                                 array_unshift( $table, false );
1359                         }
1360                 }
1361                 return $table;
1362         }
1363
1364         /**
1365          * Delete a table
1366          * @param string $tableName
1367          * @param string $fName
1368          * @return bool|ResultWrapper
1369          * @since 1.18
1370          */
1371         public function dropTable( $tableName, $fName = __METHOD__ ) {
1372                 if ( !$this->tableExists( $tableName, $fName ) ) {
1373                         return false;
1374                 }
1375
1376                 // parent function incorrectly appends CASCADE, which we don't want
1377                 $sql = "DROP TABLE " . $this->tableName( $tableName );
1378
1379                 return $this->query( $sql, $fName );
1380         }
1381
1382         /**
1383          * Called in the installer and updater.
1384          * Probably doesn't need to be called anywhere else in the codebase.
1385          * @param bool|null $value
1386          * @return bool|null
1387          */
1388         public function prepareStatements( $value = null ) {
1389                 return wfSetVar( $this->mPrepareStatements, $value );
1390         }
1391
1392         /**
1393          * Called in the installer and updater.
1394          * Probably doesn't need to be called anywhere else in the codebase.
1395          * @param bool|null $value
1396          * @return bool|null
1397          */
1398         public function scrollableCursor( $value = null ) {
1399                 return wfSetVar( $this->mScrollableCursor, $value );
1400         }
1401
1402         /**
1403          * Called in the installer and updater.
1404          * Probably doesn't need to be called anywhere else in the codebase.
1405          * @param array|null $value
1406          * @return array|null
1407          */
1408         public function ignoreErrors( array $value = null ) {
1409                 return wfSetVar( $this->mIgnoreErrors, $value );
1410         }
1411 } // end DatabaseMssql class