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