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
  42         protected $mPort;
  43
  44         public function cascadingDeletes() {
  45                 return true;
  46         }
  47
  48         public function cleanupTriggers() {
  49                 return false;
  50         }
  51
  52         public function strictIPs() {
  53                 return false;
  54         }
  55
  56         public function realTimestamps() {
  57                 return false;
  58         }
  59
  60         public function implicitGroupby() {
  61                 return false;
  62         }
  63
  64         public function implicitOrderby() {
  65                 return false;
  66         }
  67
  68         public function functionalIndexes() {
  69                 return true;
  70         }
  71
  72         public function unionSupportsOrderAndLimit() {
  73                 return false;
  74         }
  75
  76         /**
  77          * Usually aborts on failure
  78          * @param string $server
  79          * @param string $user
  80          * @param string $password
  81          * @param string $dbName
  82          * @throws DBConnectionError
  83          * @return bool|DatabaseBase|null
  84          */
  85         public function open( $server, $user, $password, $dbName ) {
  86                 # Test for driver support, to avoid suppressed fatal error
  87                 if ( !function_exists( 'sqlsrv_connect' ) ) {
  88                         throw new DBConnectionError(
  89                                 $this,
  90                                 "Microsoft SQL Server Native (sqlsrv) functions missing.
  91                                 You can download the driver from: http://go.microsoft.com/fwlink/?LinkId=123470\n"
  92                         );
  93                 }
  94
  95                 global $wgDBport, $wgDBWindowsAuthentication;
  96
  97                 # e.g. the class is being loaded
  98                 if ( !strlen( $user ) ) {
  99                         return null;
 100                 }
 101
 102                 $this->close();
 103                 $this->mServer = $server;
 104                 $this->mPort = $wgDBport;
 105                 $this->mUser = $user;
 106                 $this->mPassword = $password;
 107                 $this->mDBname = $dbName;
 108
 109                 $connectionInfo = [];
 110
 111                 if ( $dbName ) {
 112                         $connectionInfo['Database'] = $dbName;
 113                 }
 114
 115                 // Decide which auth scenerio to use
 116                 // if we are using Windows auth, don't add credentials to $connectionInfo
 117                 if ( !$wgDBWindowsAuthentication ) {
 118                         $connectionInfo['UID'] = $user;
 119                         $connectionInfo['PWD'] = $password;
 120                 }
 121
 122                 MediaWiki\suppressWarnings();
 123                 $this->mConn = sqlsrv_connect( $server, $connectionInfo );
 124                 MediaWiki\restoreWarnings();
 125
 126                 if ( $this->mConn === false ) {
 127                         throw new DBConnectionError( $this, $this->lastError() );
 128                 }
 129
 130                 $this->mOpened = true;
 131
 132                 return $this->mConn;
 133         }
 134
 135         /**
 136          * Closes a database connection, if it is open
 137          * Returns success, true if already closed
 138          * @return bool
 139          */
 140         protected function closeConnection() {
 141                 return sqlsrv_close( $this->mConn );
 142         }
 143
 144         /**
 145          * @param bool|MssqlResultWrapper|resource $result
 146          * @return bool|MssqlResultWrapper
 147          */
 148         protected function resultObject( $result ) {
 149                 if ( !$result ) {
 150                         return false;
 151                 } elseif ( $result instanceof MssqlResultWrapper ) {
 152                         return $result;
 153                 } elseif ( $result === true ) {
 154                         // Successful write query
 155                         return $result;
 156                 } else {
 157                         return new MssqlResultWrapper( $this, $result );
 158                 }
 159         }
 160
 161         /**
 162          * @param string $sql
 163          * @return bool|MssqlResult
 164          * @throws DBUnexpectedError
 165          */
 166         protected function doQuery( $sql ) {
 167                 if ( $this->debug() ) {
 168                         wfDebug( "SQL: [$sql]\n" );
 169                 }
 170                 $this->offset = 0;
 171
 172                 // several extensions seem to think that all databases support limits
 173                 // via LIMIT N after the WHERE clause well, MSSQL uses SELECT TOP N,
 174                 // so to catch any of those extensions we'll do a quick check for a
 175                 // LIMIT clause and pass $sql through $this->LimitToTopN() which parses
 176                 // the limit clause and passes the result to $this->limitResult();
 177                 if ( preg_match( '/\bLIMIT\s*/i', $sql ) ) {
 178                         // massage LIMIT -> TopN
 179                         $sql = $this->LimitToTopN( $sql );
 180                 }
 181
 182                 // MSSQL doesn't have EXTRACT(epoch FROM XXX)
 183                 if ( preg_match( '#\bEXTRACT\s*?\(\s*?EPOCH\s+FROM\b#i', $sql, $matches ) ) {
 184                         // This is same as UNIX_TIMESTAMP, we need to calc # of seconds from 1970
 185                         $sql = str_replace( $matches[0], "DATEDIFF(s,CONVERT(datetime,'1/1/1970'),", $sql );
 186                 }
 187
 188                 // perform query
 189
 190                 // SQLSRV_CURSOR_STATIC is slower than SQLSRV_CURSOR_CLIENT_BUFFERED (one of the two is
 191                 // needed if we want to be able to seek around the result set), however CLIENT_BUFFERED
 192                 // has a bug in the sqlsrv driver where wchar_t types (such as nvarchar) that are empty
 193                 // strings make php throw a fatal error "Severe error translating Unicode"
 194                 if ( $this->mScrollableCursor ) {
 195                         $scrollArr = [ 'Scrollable' => SQLSRV_CURSOR_STATIC ];
 196                 } else {
 197                         $scrollArr = [];
 198                 }
 199
 200                 if ( $this->mPrepareStatements ) {
 201                         // we do prepare + execute so we can get its field metadata for later usage if desired
 202                         $stmt = sqlsrv_prepare( $this->mConn, $sql, [], $scrollArr );
 203                         $success = sqlsrv_execute( $stmt );
 204                 } else {
 205                         $stmt = sqlsrv_query( $this->mConn, $sql, [], $scrollArr );
 206                         $success = (bool)$stmt;
 207                 }
 208
 209                 if ( $this->mIgnoreDupKeyErrors ) {
 210                         // ignore duplicate key errors, but nothing else
 211                         // this emulates INSERT IGNORE in MySQL
 212                         if ( $success === false ) {
 213                                 $errors = sqlsrv_errors( SQLSRV_ERR_ERRORS );
 214                                 $success = true;
 215
 216                                 foreach ( $errors as $err ) {
 217                                         if ( $err['SQLSTATE'] == '23000' && $err['code'] == '2601' ) {
 218                                                 continue; // duplicate key error caused by unique index
 219                                         } elseif ( $err['SQLSTATE'] == '23000' && $err['code'] == '2627' ) {
 220                                                 continue; // duplicate key error caused by primary key
 221                                         } elseif ( $err['SQLSTATE'] == '01000' && $err['code'] == '3621' ) {
 222                                                 continue; // generic "the statement has been terminated" error
 223                                         }
 224
 225                                         $success = false; // getting here means we got an error we weren't expecting
 226                                         break;
 227                                 }
 228
 229                                 if ( $success ) {
 230                                         $this->mAffectedRows = 0;
 231                                         return $stmt;
 232                                 }
 233                         }
 234                 }
 235
 236                 if ( $success === false ) {
 237                         return false;
 238                 }
 239                 // remember number of rows affected
 240                 $this->mAffectedRows = sqlsrv_rows_affected( $stmt );
 241
 242                 return $stmt;
 243         }
 244
 245         public function freeResult( $res ) {
 246                 if ( $res instanceof ResultWrapper ) {
 247                         $res = $res->result;
 248                 }
 249
 250                 sqlsrv_free_stmt( $res );
 251         }
 252
 253         /**
 254          * @param MssqlResultWrapper $res
 255          * @return stdClass
 256          */
 257         public function fetchObject( $res ) {
 258                 // $res is expected to be an instance of MssqlResultWrapper here
 259                 return $res->fetchObject();
 260         }
 261
 262         /**
 263          * @param MssqlResultWrapper $res
 264          * @return array
 265          */
 266         public function fetchRow( $res ) {
 267                 return $res->fetchRow();
 268         }
 269
 270         /**
 271          * @param mixed $res
 272          * @return int
 273          */
 274         public function numRows( $res ) {
 275                 if ( $res instanceof ResultWrapper ) {
 276                         $res = $res->result;
 277                 }
 278
 279                 return sqlsrv_num_rows( $res );
 280         }
 281
 282         /**
 283          * @param mixed $res
 284          * @return int
 285          */
 286         public function numFields( $res ) {
 287                 if ( $res instanceof ResultWrapper ) {
 288                         $res = $res->result;
 289                 }
 290
 291                 return sqlsrv_num_fields( $res );
 292         }
 293
 294         /**
 295          * @param mixed $res
 296          * @param int $n
 297          * @return int
 298          */
 299         public function fieldName( $res, $n ) {
 300                 if ( $res instanceof ResultWrapper ) {
 301                         $res = $res->result;
 302                 }
 303
 304                 return sqlsrv_field_metadata( $res )[$n]['Name'];
 305         }
 306
 307         /**
 308          * This must be called after nextSequenceVal
 309          * @return int|null
 310          */
 311         public function insertId() {
 312                 return $this->mInsertId;
 313         }
 314
 315         /**
 316          * @param MssqlResultWrapper $res
 317          * @param int $row
 318          * @return bool
 319          */
 320         public function dataSeek( $res, $row ) {
 321                 return $res->seek( $row );
 322         }
 323
 324         /**
 325          * @return string
 326          */
 327         public function lastError() {
 328                 $strRet = '';
 329                 $retErrors = sqlsrv_errors( SQLSRV_ERR_ALL );
 330                 if ( $retErrors != null ) {
 331                         foreach ( $retErrors as $arrError ) {
 332                                 $strRet .= $this->formatError( $arrError ) . "\n";
 333                         }
 334                 } else {
 335                         $strRet = "No errors found";
 336                 }
 337
 338                 return $strRet;
 339         }
 340
 341         /**
 342          * @param array $err
 343          * @return string
 344          */
 345         private function formatError( $err ) {
 346                 return '[SQLSTATE ' . $err['SQLSTATE'] . '][Error Code ' . $err['code'] . ']' . $err['message'];
 347         }
 348
 349         /**
 350          * @return string
 351          */
 352         public function lastErrno() {
 353                 $err = sqlsrv_errors( SQLSRV_ERR_ALL );
 354                 if ( $err !== null && isset( $err[0] ) ) {
 355                         return $err[0]['code'];
 356                 } else {
 357                         return 0;
 358                 }
 359         }
 360
 361         /**
 362          * @return int
 363          */
 364         public function affectedRows() {
 365                 return $this->mAffectedRows;
 366         }
 367
 368         /**
 369          * SELECT wrapper
 370          *
 371          * @param mixed $table Array or string, table name(s) (prefix auto-added)
 372          * @param mixed $vars Array or string, field name(s) to be retrieved
 373          * @param mixed $conds Array or string, condition(s) for WHERE
 374          * @param string $fname Calling function name (use __METHOD__) for logs/profiling
 375          * @param array $options Associative array of options (e.g.
 376          *   array('GROUP BY' => 'page_title')), see Database::makeSelectOptions
 377          *   code for list of supported stuff
 378          * @param array $join_conds Associative array of table join conditions
 379          *   (optional) (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 380          * @return mixed Database result resource (feed to Database::fetchObject
 381          *   or whatever), or false on failure
 382          * @throws DBQueryError
 383          * @throws DBUnexpectedError
 384          * @throws Exception
 385          */
 386         public function select( $table, $vars, $conds = '', $fname = __METHOD__,
 387                 $options = [], $join_conds = []
 388         ) {
 389                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 390                 if ( isset( $options['EXPLAIN'] ) ) {
 391                         try {
 392                                 $this->mScrollableCursor = false;
 393                                 $this->mPrepareStatements = false;
 394                                 $this->query( "SET SHOWPLAN_ALL ON" );
 395                                 $ret = $this->query( $sql, $fname );
 396                                 $this->query( "SET SHOWPLAN_ALL OFF" );
 397                         } catch ( DBQueryError $dqe ) {
 398                                 if ( isset( $options['FOR COUNT'] ) ) {
 399                                         // likely don't have privs for SHOWPLAN, so run a select count instead
 400                                         $this->query( "SET SHOWPLAN_ALL OFF" );
 401                                         unset( $options['EXPLAIN'] );
 402                                         $ret = $this->select(
 403                                                 $table,
 404                                                 'COUNT(*) AS EstimateRows',
 405                                                 $conds,
 406                                                 $fname,
 407                                                 $options,
 408                                                 $join_conds
 409                                         );
 410                                 } else {
 411                                         // someone actually wanted the query plan instead of an est row count
 412                                         // let them know of the error
 413                                         $this->mScrollableCursor = true;
 414                                         $this->mPrepareStatements = true;
 415                                         throw $dqe;
 416                                 }
 417                         }
 418                         $this->mScrollableCursor = true;
 419                         $this->mPrepareStatements = true;
 420                         return $ret;
 421                 }
 422                 return $this->query( $sql, $fname );
 423         }
 424
 425         /**
 426          * SELECT wrapper
 427          *
 428          * @param mixed $table Array or string, table name(s) (prefix auto-added)
 429          * @param mixed $vars Array or string, field name(s) to be retrieved
 430          * @param mixed $conds Array or string, condition(s) for WHERE
 431          * @param string $fname Calling function name (use __METHOD__) for logs/profiling
 432          * @param array $options Associative array of options (e.g. array('GROUP BY' => 'page_title')),
 433          *   see Database::makeSelectOptions code for list of supported stuff
 434          * @param array $join_conds Associative array of table join conditions (optional)
 435          *    (e.g. array( 'page' => array('LEFT JOIN','page_latest=rev_id') )
 436          * @return string The SQL text
 437          */
 438         public function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 439                 $options = [], $join_conds = []
 440         ) {
 441                 if ( isset( $options['EXPLAIN'] ) ) {
 442                         unset( $options['EXPLAIN'] );
 443                 }
 444
 445                 $sql = parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 446
 447                 // try to rewrite aggregations of bit columns (currently MAX and MIN)
 448                 if ( strpos( $sql, 'MAX(' ) !== false || strpos( $sql, 'MIN(' ) !== false ) {
 449                         $bitColumns = [];
 450                         if ( is_array( $table ) ) {
 451                                 foreach ( $table as $t ) {
 452                                         $bitColumns += $this->getBitColumns( $this->tableName( $t ) );
 453                                 }
 454                         } else {
 455                                 $bitColumns = $this->getBitColumns( $this->tableName( $table ) );
 456                         }
 457
 458                         foreach ( $bitColumns as $col => $info ) {
 459                                 $replace = [
 460                                         "MAX({$col})" => "MAX(CAST({$col} AS tinyint))",
 461                                         "MIN({$col})" => "MIN(CAST({$col} AS tinyint))",
 462                                 ];
 463                                 $sql = str_replace( array_keys( $replace ), array_values( $replace ), $sql );
 464                         }
 465                 }
 466
 467                 return $sql;
 468         }
 469
 470         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
 471                 $fname = __METHOD__
 472         ) {
 473                 $this->mScrollableCursor = false;
 474                 try {
 475                         parent::deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname );
 476                 } catch ( Exception $e ) {
 477                         $this->mScrollableCursor = true;
 478                         throw $e;
 479                 }
 480                 $this->mScrollableCursor = true;
 481         }
 482
 483         public function delete( $table, $conds, $fname = __METHOD__ ) {
 484                 $this->mScrollableCursor = false;
 485                 try {
 486                         parent::delete( $table, $conds, $fname );
 487                 } catch ( Exception $e ) {
 488                         $this->mScrollableCursor = true;
 489                         throw $e;
 490                 }
 491                 $this->mScrollableCursor = true;
 492         }
 493
 494         /**
 495          * Estimate rows in dataset
 496          * Returns estimated count, based on SHOWPLAN_ALL output
 497          * This is not necessarily an accurate estimate, so use sparingly
 498          * Returns -1 if count cannot be found
 499          * Takes same arguments as Database::select()
 500          * @param string $table
 501          * @param string $vars
 502          * @param string $conds
 503          * @param string $fname
 504          * @param array $options
 505          * @return int
 506          */
 507         public function estimateRowCount( $table, $vars = '*', $conds = '',
 508                 $fname = __METHOD__, $options = []
 509         ) {
 510                 // http://msdn2.microsoft.com/en-us/library/aa259203.aspx
 511                 $options['EXPLAIN'] = true;
 512                 $options['FOR COUNT'] = true;
 513                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 514
 515                 $rows = -1;
 516                 if ( $res ) {
 517                         $row = $this->fetchRow( $res );
 518
 519                         if ( isset( $row['EstimateRows'] ) ) {
 520                                 $rows = (int)$row['EstimateRows'];
 521                         }
 522                 }
 523
 524                 return $rows;
 525         }
 526
 527         /**
 528          * Returns information about an index
 529          * If errors are explicitly ignored, returns NULL on failure
 530          * @param string $table
 531          * @param string $index
 532          * @param string $fname
 533          * @return array|bool|null
 534          */
 535         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 536                 # This does not return the same info as MYSQL would, but that's OK
 537                 # because MediaWiki never uses the returned value except to check for
 538                 # the existance of indexes.
 539                 $sql = "sp_helpindex '" . $table . "'";
 540                 $res = $this->query( $sql, $fname );
 541                 if ( !$res ) {
 542                         return null;
 543                 }
 544
 545                 $result = [];
 546                 foreach ( $res as $row ) {
 547                         if ( $row->index_name == $index ) {
 548                                 $row->Non_unique = !stristr( $row->index_description, "unique" );
 549                                 $cols = explode( ", ", $row->index_keys );
 550                                 foreach ( $cols as $col ) {
 551                                         $row->Column_name = trim( $col );
 552                                         $result[] = clone $row;
 553                                 }
 554                         } elseif ( $index == 'PRIMARY' && stristr( $row->index_description, 'PRIMARY' ) ) {
 555                                 $row->Non_unique = 0;
 556                                 $cols = explode( ", ", $row->index_keys );
 557                                 foreach ( $cols as $col ) {
 558                                         $row->Column_name = trim( $col );
 559                                         $result[] = clone $row;
 560                                 }
 561                         }
 562                 }
 563
 564                 return empty( $result ) ? false : $result;
 565         }
 566
 567         /**
 568          * INSERT wrapper, inserts an array into a table
 569          *
 570          * $arrToInsert may be a single associative array, or an array of these with numeric keys, for
 571          * multi-row insert.
 572          *
 573          * Usually aborts on failure
 574          * If errors are explicitly ignored, returns success
 575          * @param string $table
 576          * @param array $arrToInsert
 577          * @param string $fname
 578          * @param array $options
 579          * @return bool
 580          * @throws Exception
 581          */
 582         public function insert( $table, $arrToInsert, $fname = __METHOD__, $options = [] ) {
 583                 # No rows to insert, easy just return now
 584                 if ( !count( $arrToInsert ) ) {
 585                         return true;
 586                 }
 587
 588                 if ( !is_array( $options ) ) {
 589                         $options = [ $options ];
 590                 }
 591
 592                 $table = $this->tableName( $table );
 593
 594                 if ( !( isset( $arrToInsert[0] ) && is_array( $arrToInsert[0] ) ) ) { // Not multi row
 595                         $arrToInsert = [ 0 => $arrToInsert ]; // make everything multi row compatible
 596                 }
 597
 598                 // We know the table we're inserting into, get its identity column
 599                 $identity = null;
 600                 // strip matching square brackets and the db/schema from table name
 601                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
 602                 $tableRaw = array_pop( $tableRawArr );
 603                 $res = $this->doQuery(
 604                         "SELECT NAME AS idColumn FROM SYS.IDENTITY_COLUMNS " .
 605                                 "WHERE OBJECT_NAME(OBJECT_ID)='{$tableRaw}'"
 606                 );
 607                 if ( $res && sqlsrv_has_rows( $res ) ) {
 608                         // There is an identity for this table.
 609                         $identityArr = sqlsrv_fetch_array( $res, SQLSRV_FETCH_ASSOC );
 610                         $identity = array_pop( $identityArr );
 611                 }
 612                 sqlsrv_free_stmt( $res );
 613
 614                 // Determine binary/varbinary fields so we can encode data as a hex string like 0xABCDEF
 615                 $binaryColumns = $this->getBinaryColumns( $table );
 616
 617                 // INSERT IGNORE is not supported by SQL Server
 618                 // remove IGNORE from options list and set ignore flag to true
 619                 if ( in_array( 'IGNORE', $options ) ) {
 620                         $options = array_diff( $options, [ 'IGNORE' ] );
 621                         $this->mIgnoreDupKeyErrors = true;
 622                 }
 623
 624                 foreach ( $arrToInsert as $a ) {
 625                         // start out with empty identity column, this is so we can return
 626                         // it as a result of the insert logic
 627                         $sqlPre = '';
 628                         $sqlPost = '';
 629                         $identityClause = '';
 630
 631                         // if we have an identity column
 632                         if ( $identity ) {
 633                                 // iterate through
 634                                 foreach ( $a as $k => $v ) {
 635                                         if ( $k == $identity ) {
 636                                                 if ( !is_null( $v ) ) {
 637                                                         // there is a value being passed to us,
 638                                                         // we need to turn on and off inserted identity
 639                                                         $sqlPre = "SET IDENTITY_INSERT $table ON;";
 640                                                         $sqlPost = ";SET IDENTITY_INSERT $table OFF;";
 641                                                 } else {
 642                                                         // we can't insert NULL into an identity column,
 643                                                         // so remove the column from the insert.
 644                                                         unset( $a[$k] );
 645                                                 }
 646                                         }
 647                                 }
 648
 649                                 // we want to output an identity column as result
 650                                 $identityClause = "OUTPUT INSERTED.$identity ";
 651                         }
 652
 653                         $keys = array_keys( $a );
 654
 655                         // Build the actual query
 656                         $sql = $sqlPre . 'INSERT ' . implode( ' ', $options ) .
 657                                 " INTO $table (" . implode( ',', $keys ) . ") $identityClause VALUES (";
 658
 659                         $first = true;
 660                         foreach ( $a as $key => $value ) {
 661                                 if ( isset( $binaryColumns[$key] ) ) {
 662                                         $value = new MssqlBlob( $value );
 663                                 }
 664                                 if ( $first ) {
 665                                         $first = false;
 666                                 } else {
 667                                         $sql .= ',';
 668                                 }
 669                                 if ( is_null( $value ) ) {
 670                                         $sql .= 'null';
 671                                 } elseif ( is_array( $value ) || is_object( $value ) ) {
 672                                         if ( is_object( $value ) && $value instanceof Blob ) {
 673                                                 $sql .= $this->addQuotes( $value );
 674                                         } else {
 675                                                 $sql .= $this->addQuotes( serialize( $value ) );
 676                                         }
 677                                 } else {
 678                                         $sql .= $this->addQuotes( $value );
 679                                 }
 680                         }
 681                         $sql .= ')' . $sqlPost;
 682
 683                         // Run the query
 684                         $this->mScrollableCursor = false;
 685                         try {
 686                                 $ret = $this->query( $sql );
 687                         } catch ( Exception $e ) {
 688                                 $this->mScrollableCursor = true;
 689                                 $this->mIgnoreDupKeyErrors = false;
 690                                 throw $e;
 691                         }
 692                         $this->mScrollableCursor = true;
 693
 694                         if ( !is_null( $identity ) ) {
 695                                 // then we want to get the identity column value we were assigned and save it off
 696                                 $row = $ret->fetchObject();
 697                                 if ( is_object( $row ) ) {
 698                                         $this->mInsertId = $row->$identity;
 699                                 }
 700                         }
 701                 }
 702                 $this->mIgnoreDupKeyErrors = false;
 703                 return $ret;
 704         }
 705
 706         /**
 707          * INSERT SELECT wrapper
 708          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
 709          * Source items may be literals rather than field names, but strings should
 710          * be quoted with Database::addQuotes().
 711          * @param string $destTable
 712          * @param array|string $srcTable May be an array of tables.
 713          * @param array $varMap
 714          * @param array $conds May be "*" to copy the whole table.
 715          * @param string $fname
 716          * @param array $insertOptions
 717          * @param array $selectOptions
 718          * @return null|ResultWrapper
 719          * @throws Exception
 720          */
 721         public function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 722                 $insertOptions = [], $selectOptions = []
 723         ) {
 724                 $this->mScrollableCursor = false;
 725                 try {
 726                         $ret = parent::insertSelect(
 727                                 $destTable,
 728                                 $srcTable,
 729                                 $varMap,
 730                                 $conds,
 731                                 $fname,
 732                                 $insertOptions,
 733                                 $selectOptions
 734                         );
 735                 } catch ( Exception $e ) {
 736                         $this->mScrollableCursor = true;
 737                         throw $e;
 738                 }
 739                 $this->mScrollableCursor = true;
 740
 741                 return $ret;
 742         }
 743
 744         /**
 745          * UPDATE wrapper. Takes a condition array and a SET array.
 746          *
 747          * @param string $table Name of the table to UPDATE. This will be passed through
 748          *                DatabaseBase::tableName().
 749          *
 750          * @param array $values An array of values to SET. For each array element,
 751          *                the key gives the field name, and the value gives the data
 752          *                to set that field to. The data will be quoted by
 753          *                DatabaseBase::addQuotes().
 754          *
 755          * @param array $conds An array of conditions (WHERE). See
 756          *                DatabaseBase::select() for the details of the format of
 757          *                condition arrays. Use '*' to update all rows.
 758          *
 759          * @param string $fname The function name of the caller (from __METHOD__),
 760          *                for logging and profiling.
 761          *
 762          * @param array $options An array of UPDATE options, can be:
 763          *                   - IGNORE: Ignore unique key conflicts
 764          *                   - LOW_PRIORITY: MySQL-specific, see MySQL manual.
 765          * @return bool
 766          * @throws DBUnexpectedError
 767          * @throws Exception
 768          * @throws MWException
 769          */
 770         function update( $table, $values, $conds, $fname = __METHOD__, $options = [] ) {
 771                 $table = $this->tableName( $table );
 772                 $binaryColumns = $this->getBinaryColumns( $table );
 773
 774                 $opts = $this->makeUpdateOptions( $options );
 775                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET, $binaryColumns );
 776
 777                 if ( $conds !== [] && $conds !== '*' ) {
 778                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND, $binaryColumns );
 779                 }
 780
 781                 $this->mScrollableCursor = false;
 782                 try {
 783                         $ret = $this->query( $sql );
 784                 } catch ( Exception $e ) {
 785                         $this->mScrollableCursor = true;
 786                         throw $e;
 787                 }
 788                 $this->mScrollableCursor = true;
 789                 return true;
 790         }
 791
 792         /**
 793          * Makes an encoded list of strings from an array
 794          * @param array $a Containing the data
 795          * @param int $mode Constant
 796          *      - LIST_COMMA:          comma separated, no field names
 797          *      - LIST_AND:            ANDed WHERE clause (without the WHERE). See
 798          *        the documentation for $conds in DatabaseBase::select().
 799          *      - LIST_OR:             ORed WHERE clause (without the WHERE)
 800          *      - LIST_SET:            comma separated with field names, like a SET clause
 801          *      - LIST_NAMES:          comma separated field names
 802          * @param array $binaryColumns Contains a list of column names that are binary types
 803          *      This is a custom parameter only present for MS SQL.
 804          *
 805          * @throws MWException|DBUnexpectedError
 806          * @return string
 807          */
 808         public function makeList( $a, $mode = LIST_COMMA, $binaryColumns = [] ) {
 809                 if ( !is_array( $a ) ) {
 810                         throw new DBUnexpectedError( $this,
 811                                 'DatabaseBase::makeList called with incorrect parameters' );
 812                 }
 813
 814                 if ( $mode != LIST_NAMES ) {
 815                         // In MS SQL, values need to be specially encoded when they are
 816                         // inserted into binary fields. Perform this necessary encoding
 817                         // for the specified set of columns.
 818                         foreach ( array_keys( $a ) as $field ) {
 819                                 if ( !isset( $binaryColumns[$field] ) ) {
 820                                         continue;
 821                                 }
 822
 823                                 if ( is_array( $a[$field] ) ) {
 824                                         foreach ( $a[$field] as &$v ) {
 825                                                 $v = new MssqlBlob( $v );
 826                                         }
 827                                         unset( $v );
 828                                 } else {
 829                                         $a[$field] = new MssqlBlob( $a[$field] );
 830                                 }
 831                         }
 832                 }
 833
 834                 return parent::makeList( $a, $mode );
 835         }
 836
 837         /**
 838          * @param string $table
 839          * @param string $field
 840          * @return int Returns the size of a text field, or -1 for "unlimited"
 841          */
 842         public function textFieldSize( $table, $field ) {
 843                 $table = $this->tableName( $table );
 844                 $sql = "SELECT CHARACTER_MAXIMUM_LENGTH,DATA_TYPE FROM INFORMATION_SCHEMA.Columns
 845                         WHERE TABLE_NAME = '$table' AND COLUMN_NAME = '$field'";
 846                 $res = $this->query( $sql );
 847                 $row = $this->fetchRow( $res );
 848                 $size = -1;
 849                 if ( strtolower( $row['DATA_TYPE'] ) != 'text' ) {
 850                         $size = $row['CHARACTER_MAXIMUM_LENGTH'];
 851                 }
 852
 853                 return $size;
 854         }
 855
 856         /**
 857          * Construct a LIMIT query with optional offset
 858          * This is used for query pages
 859          *
 860          * @param string $sql SQL query we will append the limit too
 861          * @param int $limit The SQL limit
 862          * @param bool|int $offset The SQL offset (default false)
 863          * @return array|string
 864          * @throws DBUnexpectedError
 865          */
 866         public function limitResult( $sql, $limit, $offset = false ) {
 867                 if ( $offset === false || $offset == 0 ) {
 868                         if ( strpos( $sql, "SELECT" ) === false ) {
 869                                 return "TOP {$limit} " . $sql;
 870                         } else {
 871                                 return preg_replace( '/\bSELECT(\s+DISTINCT)?\b/Dsi',
 872                                         'SELECT$1 TOP ' . $limit, $sql, 1 );
 873                         }
 874                 } else {
 875                         // This one is fun, we need to pull out the select list as well as any ORDER BY clause
 876                         $select = $orderby = [];
 877                         $s1 = preg_match( '#SELECT\s+(.+?)\s+FROM#Dis', $sql, $select );
 878                         $s2 = preg_match( '#(ORDER BY\s+.+?)(\s*FOR XML .*)?$#Dis', $sql, $orderby );
 879                         $overOrder = $postOrder = '';
 880                         $first = $offset + 1;
 881                         $last = $offset + $limit;
 882                         $sub1 = 'sub_' . $this->mSubqueryId;
 883                         $sub2 = 'sub_' . ( $this->mSubqueryId + 1 );
 884                         $this->mSubqueryId += 2;
 885                         if ( !$s1 ) {
 886                                 // wat
 887                                 throw new DBUnexpectedError( $this, "Attempting to LIMIT a non-SELECT query\n" );
 888                         }
 889                         if ( !$s2 ) {
 890                                 // no ORDER BY
 891                                 $overOrder = 'ORDER BY (SELECT 1)';
 892                         } else {
 893                                 if ( !isset( $orderby[2] ) || !$orderby[2] ) {
 894                                         // don't need to strip it out if we're using a FOR XML clause
 895                                         $sql = str_replace( $orderby[1], '', $sql );
 896                                 }
 897                                 $overOrder = $orderby[1];
 898                                 $postOrder = ' ' . $overOrder;
 899                         }
 900                         $sql = "SELECT {$select[1]}
 901                                         FROM (
 902                                                 SELECT ROW_NUMBER() OVER({$overOrder}) AS rowNumber, *
 903                                                 FROM ({$sql}) {$sub1}
 904                                         ) {$sub2}
 905                                         WHERE rowNumber BETWEEN {$first} AND {$last}{$postOrder}";
 906
 907                         return $sql;
 908                 }
 909         }
 910
 911         /**
 912          * If there is a limit clause, parse it, strip it, and pass the remaining
 913          * SQL through limitResult() with the appropriate parameters. Not the
 914          * prettiest solution, but better than building a whole new parser. This
 915          * exists becase there are still too many extensions that don't use dynamic
 916          * sql generation.
 917          *
 918          * @param string $sql
 919          * @return array|mixed|string
 920          */
 921         public function LimitToTopN( $sql ) {
 922                 // Matches: LIMIT {[offset,] row_count | row_count OFFSET offset}
 923                 $pattern = '/\bLIMIT\s+((([0-9]+)\s*,\s*)?([0-9]+)(\s+OFFSET\s+([0-9]+))?)/i';
 924                 if ( preg_match( $pattern, $sql, $matches ) ) {
 925                         $row_count = $matches[4];
 926                         $offset = $matches[3] ?: $matches[6] ?: false;
 927
 928                         // strip the matching LIMIT clause out
 929                         $sql = str_replace( $matches[0], '', $sql );
 930
 931                         return $this->limitResult( $sql, $row_count, $offset );
 932                 }
 933
 934                 return $sql;
 935         }
 936
 937         /**
 938          * @return string Wikitext of a link to the server software's web site
 939          */
 940         public function getSoftwareLink() {
 941                 return "[{{int:version-db-mssql-url}} MS SQL Server]";
 942         }
 943
 944         /**
 945          * @return string Version information from the database
 946          */
 947         public function getServerVersion() {
 948                 $server_info = sqlsrv_server_info( $this->mConn );
 949                 $version = 'Error';
 950                 if ( isset( $server_info['SQLServerVersion'] ) ) {
 951                         $version = $server_info['SQLServerVersion'];
 952                 }
 953
 954                 return $version;
 955         }
 956
 957         /**
 958          * @param string $table
 959          * @param string $fname
 960          * @return bool
 961          */
 962         public function tableExists( $table, $fname = __METHOD__ ) {
 963                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
 964
 965                 if ( $db !== false ) {
 966                         // remote database
 967                         wfDebug( "Attempting to call tableExists on a remote table" );
 968                         return false;
 969                 }
 970
 971                 if ( $schema === false ) {
 972                         global $wgDBmwschema;
 973                         $schema = $wgDBmwschema;
 974                 }
 975
 976                 $res = $this->query( "SELECT 1 FROM INFORMATION_SCHEMA.TABLES
 977                         WHERE TABLE_TYPE = 'BASE TABLE'
 978                         AND TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table'" );
 979
 980                 if ( $res->numRows() ) {
 981                         return true;
 982                 } else {
 983                         return false;
 984                 }
 985         }
 986
 987         /**
 988          * Query whether a given column exists in the mediawiki schema
 989          * @param string $table
 990          * @param string $field
 991          * @param string $fname
 992          * @return bool
 993          */
 994         public function fieldExists( $table, $field, $fname = __METHOD__ ) {
 995                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
 996
 997                 if ( $db !== false ) {
 998                         // remote database
 999                         wfDebug( "Attempting to call fieldExists on a remote table" );
1000                         return false;
1001                 }
1002
1003                 $res = $this->query( "SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS
1004                         WHERE TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table' AND COLUMN_NAME = '$field'" );
1005
1006                 if ( $res->numRows() ) {
1007                         return true;
1008                 } else {
1009                         return false;
1010                 }
1011         }
1012
1013         public function fieldInfo( $table, $field ) {
1014                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
1015
1016                 if ( $db !== false ) {
1017                         // remote database
1018                         wfDebug( "Attempting to call fieldInfo on a remote table" );
1019                         return false;
1020                 }
1021
1022                 $res = $this->query( "SELECT * FROM INFORMATION_SCHEMA.COLUMNS
1023                         WHERE TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table' AND COLUMN_NAME = '$field'" );
1024
1025                 $meta = $res->fetchRow();
1026                 if ( $meta ) {
1027                         return new MssqlField( $meta );
1028                 }
1029
1030                 return false;
1031         }
1032
1033         /**
1034          * Begin a transaction, committing any previously open transaction
1035          * @param string $fname
1036          */
1037         protected function doBegin( $fname = __METHOD__ ) {
1038                 sqlsrv_begin_transaction( $this->mConn );
1039                 $this->mTrxLevel = 1;
1040         }
1041
1042         /**
1043          * End a transaction
1044          * @param string $fname
1045          */
1046         protected function doCommit( $fname = __METHOD__ ) {
1047                 sqlsrv_commit( $this->mConn );
1048                 $this->mTrxLevel = 0;
1049         }
1050
1051         /**
1052          * Rollback a transaction.
1053          * No-op on non-transactional databases.
1054          * @param string $fname
1055          */
1056         protected function doRollback( $fname = __METHOD__ ) {
1057                 sqlsrv_rollback( $this->mConn );
1058                 $this->mTrxLevel = 0;
1059         }
1060
1061         /**
1062          * Escapes a identifier for use inm SQL.
1063          * Throws an exception if it is invalid.
1064          * Reference: http://msdn.microsoft.com/en-us/library/aa224033%28v=SQL.80%29.aspx
1065          * @param string $identifier
1066          * @throws MWException
1067          * @return string
1068          */
1069         private function escapeIdentifier( $identifier ) {
1070                 if ( strlen( $identifier ) == 0 ) {
1071                         throw new MWException( "An identifier must not be empty" );
1072                 }
1073                 if ( strlen( $identifier ) > 128 ) {
1074                         throw new MWException( "The identifier '$identifier' is too long (max. 128)" );
1075                 }
1076                 if ( ( strpos( $identifier, '[' ) !== false )
1077                         || ( strpos( $identifier, ']' ) !== false )
1078                 ) {
1079                         // It may be allowed if you quoted with double quotation marks, but
1080                         // that would break if QUOTED_IDENTIFIER is OFF
1081                         throw new MWException( "Square brackets are not allowed in '$identifier'" );
1082                 }
1083
1084                 return "[$identifier]";
1085         }
1086
1087         /**
1088          * @param string $s
1089          * @return string
1090          */
1091         public function strencode( $s ) {
1092                 // Should not be called by us
1093
1094                 return str_replace( "'", "''", $s );
1095         }
1096
1097         /**
1098          * @param string|Blob $s
1099          * @return string
1100          */
1101         public function addQuotes( $s ) {
1102                 if ( $s instanceof MssqlBlob ) {
1103                         return $s->fetch();
1104                 } elseif ( $s instanceof Blob ) {
1105                         // this shouldn't really ever be called, but it's here if needed
1106                         // (and will quite possibly make the SQL error out)
1107                         $blob = new MssqlBlob( $s->fetch() );
1108                         return $blob->fetch();
1109                 } else {
1110                         if ( is_bool( $s ) ) {
1111                                 $s = $s ? 1 : 0;
1112                         }
1113                         return parent::addQuotes( $s );
1114                 }
1115         }
1116
1117         /**
1118          * @param string $s
1119          * @return string
1120          */
1121         public function addIdentifierQuotes( $s ) {
1122                 // http://msdn.microsoft.com/en-us/library/aa223962.aspx
1123                 return '[' . $s . ']';
1124         }
1125
1126         /**
1127          * @param string $name
1128          * @return bool
1129          */
1130         public function isQuotedIdentifier( $name ) {
1131                 return strlen( $name ) && $name[0] == '[' && substr( $name, -1, 1 ) == ']';
1132         }
1133
1134         /**
1135          * MS SQL supports more pattern operators than other databases (ex: [,],^)
1136          *
1137          * @param string $s
1138          * @return string
1139          */
1140         protected function escapeLikeInternal( $s ) {
1141                 return addcslashes( $s, '\%_[]^' );
1142         }
1143
1144         /**
1145          * MS SQL requires specifying the escape character used in a LIKE query
1146          * or using Square brackets to surround characters that are to be escaped
1147          * http://msdn.microsoft.com/en-us/library/ms179859.aspx
1148          * Here we take the Specify-Escape-Character approach since it's less
1149          * invasive, renders a query that is closer to other DB's and better at
1150          * handling square bracket escaping
1151          *
1152          * @return string Fully built LIKE statement
1153          */
1154         public function buildLike() {
1155                 $params = func_get_args();
1156                 if ( count( $params ) > 0 && is_array( $params[0] ) ) {
1157                         $params = $params[0];
1158                 }
1159
1160                 return parent::buildLike( $params ) . " ESCAPE '\' ";
1161         }
1162
1163         /**
1164          * @param string $db
1165          * @return bool
1166          */
1167         public function selectDB( $db ) {
1168                 try {
1169                         $this->mDBname = $db;
1170                         $this->query( "USE $db" );
1171                         return true;
1172                 } catch ( Exception $e ) {
1173                         return false;
1174                 }
1175         }
1176
1177         /**
1178          * @param array $options An associative array of options to be turned into
1179          *   an SQL query, valid keys are listed in the function.
1180          * @return array
1181          */
1182         public function makeSelectOptions( $options ) {
1183                 $tailOpts = '';
1184                 $startOpts = '';
1185
1186                 $noKeyOptions = [];
1187                 foreach ( $options as $key => $option ) {
1188                         if ( is_numeric( $key ) ) {
1189                                 $noKeyOptions[$option] = true;
1190                         }
1191                 }
1192
1193                 $tailOpts .= $this->makeGroupByWithHaving( $options );
1194
1195                 $tailOpts .= $this->makeOrderBy( $options );
1196
1197                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1198                         $startOpts .= 'DISTINCT';
1199                 }
1200
1201                 if ( isset( $noKeyOptions['FOR XML'] ) ) {
1202                         // used in group concat field emulation
1203                         $tailOpts .= " FOR XML PATH('')";
1204                 }
1205
1206                 // we want this to be compatible with the output of parent::makeSelectOptions()
1207                 return [ $startOpts, '', $tailOpts, '' ];
1208         }
1209
1210         /**
1211          * Get the type of the DBMS, as it appears in $wgDBtype.
1212          * @return string
1213          */
1214         public function getType() {
1215                 return 'mssql';
1216         }
1217
1218         /**
1219          * @param array $stringList
1220          * @return string
1221          */
1222         public function buildConcat( $stringList ) {
1223                 return implode( ' + ', $stringList );
1224         }
1225
1226         /**
1227          * Build a GROUP_CONCAT or equivalent statement for a query.
1228          * MS SQL doesn't have GROUP_CONCAT so we emulate it with other stuff (and boy is it nasty)
1229          *
1230          * This is useful for combining a field for several rows into a single string.
1231          * NULL values will not appear in the output, duplicated values will appear,
1232          * and the resulting delimiter-separated values have no defined sort order.
1233          * Code using the results may need to use the PHP unique() or sort() methods.
1234          *
1235          * @param string $delim Glue to bind the results together
1236          * @param string|array $table Table name
1237          * @param string $field Field name
1238          * @param string|array $conds Conditions
1239          * @param string|array $join_conds Join conditions
1240          * @return string SQL text
1241          * @since 1.23
1242          */
1243         public function buildGroupConcatField( $delim, $table, $field, $conds = '',
1244                 $join_conds = []
1245         ) {
1246                 $gcsq = 'gcsq_' . $this->mSubqueryId;
1247                 $this->mSubqueryId++;
1248
1249                 $delimLen = strlen( $delim );
1250                 $fld = "{$field} + {$this->addQuotes( $delim )}";
1251                 $sql = "(SELECT LEFT({$field}, LEN({$field}) - {$delimLen}) FROM ("
1252                         . $this->selectSQLText( $table, $fld, $conds, null, [ 'FOR XML' ], $join_conds )
1253                         . ") {$gcsq} ({$field}))";
1254
1255                 return $sql;
1256         }
1257
1258         /**
1259          * @return string
1260          */
1261         public function getSearchEngine() {
1262                 return "SearchMssql";
1263         }
1264
1265         /**
1266          * Returns an associative array for fields that are of type varbinary, binary, or image
1267          * $table can be either a raw table name or passed through tableName() first
1268          * @param string $table
1269          * @return array
1270          */
1271         private function getBinaryColumns( $table ) {
1272                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
1273                 $tableRaw = array_pop( $tableRawArr );
1274
1275                 if ( $this->mBinaryColumnCache === null ) {
1276                         $this->populateColumnCaches();
1277                 }
1278
1279                 return isset( $this->mBinaryColumnCache[$tableRaw] )
1280                         ? $this->mBinaryColumnCache[$tableRaw]
1281                         : [];
1282         }
1283
1284         /**
1285          * @param string $table
1286          * @return array
1287          */
1288         private function getBitColumns( $table ) {
1289                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
1290                 $tableRaw = array_pop( $tableRawArr );
1291
1292                 if ( $this->mBitColumnCache === null ) {
1293                         $this->populateColumnCaches();
1294                 }
1295
1296                 return isset( $this->mBitColumnCache[$tableRaw] )
1297                         ? $this->mBitColumnCache[$tableRaw]
1298                         : [];
1299         }
1300
1301         private function populateColumnCaches() {
1302                 $res = $this->select( 'INFORMATION_SCHEMA.COLUMNS', '*',
1303                         [
1304                                 'TABLE_CATALOG' => $this->mDBname,
1305                                 'TABLE_SCHEMA' => $this->mSchema,
1306                                 'DATA_TYPE' => [ 'varbinary', 'binary', 'image', 'bit' ]
1307                         ] );
1308
1309                 $this->mBinaryColumnCache = [];
1310                 $this->mBitColumnCache = [];
1311                 foreach ( $res as $row ) {
1312                         if ( $row->DATA_TYPE == 'bit' ) {
1313                                 $this->mBitColumnCache[$row->TABLE_NAME][$row->COLUMN_NAME] = $row;
1314                         } else {
1315                                 $this->mBinaryColumnCache[$row->TABLE_NAME][$row->COLUMN_NAME] = $row;
1316                         }
1317                 }
1318         }
1319
1320         /**
1321          * @param string $name
1322          * @param string $format
1323          * @return string
1324          */
1325         function tableName( $name, $format = 'quoted' ) {
1326                 # Replace reserved words with better ones
1327                 switch ( $name ) {
1328                         case 'user':
1329                                 return $this->realTableName( 'mwuser', $format );
1330                         default:
1331                                 return $this->realTableName( $name, $format );
1332                 }
1333         }
1334
1335         /**
1336          * call this instead of tableName() in the updater when renaming tables
1337          * @param string $name
1338          * @param string $format One of quoted, raw, or split
1339          * @return string
1340          */
1341         function realTableName( $name, $format = 'quoted' ) {
1342                 $table = parent::tableName( $name, $format );
1343                 if ( $format == 'split' ) {
1344                         // Used internally, we want the schema split off from the table name and returned
1345                         // as a list with 3 elements (database, schema, table)
1346                         $table = explode( '.', $table );
1347                         while ( count( $table ) < 3 ) {
1348                                 array_unshift( $table, false );
1349                         }
1350                 }
1351                 return $table;
1352         }
1353
1354         /**
1355          * Called in the installer and updater.
1356          * Probably doesn't need to be called anywhere else in the codebase.
1357          * @param bool|null $value
1358          * @return bool|null
1359          */
1360         public function prepareStatements( $value = null ) {
1361                 return wfSetVar( $this->mPrepareStatements, $value );
1362         }
1363
1364         /**
1365          * Called in the installer and updater.
1366          * Probably doesn't need to be called anywhere else in the codebase.
1367          * @param bool|null $value
1368          * @return bool|null
1369          */
1370         public function scrollableCursor( $value = null ) {
1371                 return wfSetVar( $this->mScrollableCursor, $value );
1372         }
1373 } // end DatabaseMssql class
1374
1375 /**
1376  * Utility class.
1377  *
1378  * @ingroup Database
1379  */
1380 class MssqlField implements Field {
1381         private $name, $tableName, $default, $max_length, $nullable, $type;
1382
1383         function __construct( $info ) {
1384                 $this->name = $info['COLUMN_NAME'];
1385                 $this->tableName = $info['TABLE_NAME'];
1386                 $this->default = $info['COLUMN_DEFAULT'];
1387                 $this->max_length = $info['CHARACTER_MAXIMUM_LENGTH'];
1388                 $this->nullable = !( strtolower( $info['IS_NULLABLE'] ) == 'no' );
1389                 $this->type = $info['DATA_TYPE'];
1390         }
1391
1392         function name() {
1393                 return $this->name;
1394         }
1395
1396         function tableName() {
1397                 return $this->tableName;
1398         }
1399
1400         function defaultValue() {
1401                 return $this->default;
1402         }
1403
1404         function maxLength() {
1405                 return $this->max_length;
1406         }
1407
1408         function isNullable() {
1409                 return $this->nullable;
1410         }
1411
1412         function type() {
1413                 return $this->type;
1414         }
1415 }
1416
1417 class MssqlBlob extends Blob {
1418         public function __construct( $data ) {
1419                 if ( $data instanceof MssqlBlob ) {
1420                         return $data;
1421                 } elseif ( $data instanceof Blob ) {
1422                         $this->mData = $data->fetch();
1423                 } elseif ( is_array( $data ) && is_object( $data ) ) {
1424                         $this->mData = serialize( $data );
1425                 } else {
1426                         $this->mData = $data;
1427                 }
1428         }
1429
1430         /**
1431          * Returns an unquoted hex representation of a binary string
1432          * for insertion into varbinary-type fields
1433          * @return string
1434          */
1435         public function fetch() {
1436                 if ( $this->mData === null ) {
1437                         return 'null';
1438                 }
1439
1440                 $ret = '0x';
1441                 $dataLength = strlen( $this->mData );
1442                 for ( $i = 0; $i < $dataLength; $i++ ) {
1443                         $ret .= bin2hex( pack( 'C', ord( $this->mData[$i] ) ) );
1444                 }
1445
1446                 return $ret;
1447         }
1448 }
1449
1450 class MssqlResultWrapper extends ResultWrapper {
1451         private $mSeekTo = null;
1452
1453         /**
1454          * @return stdClass|bool
1455          */
1456         public function fetchObject() {
1457                 $res = $this->result;
1458
1459                 if ( $this->mSeekTo !== null ) {
1460                         $result = sqlsrv_fetch_object( $res, 'stdClass', [],
1461                                 SQLSRV_SCROLL_ABSOLUTE, $this->mSeekTo );
1462                         $this->mSeekTo = null;
1463                 } else {
1464                         $result = sqlsrv_fetch_object( $res );
1465                 }
1466
1467                 // MediaWiki expects us to return boolean false when there are no more rows instead of null
1468                 if ( $result === null ) {
1469                         return false;
1470                 }
1471
1472                 return $result;
1473         }
1474
1475         /**
1476          * @return array|bool
1477          */
1478         public function fetchRow() {
1479                 $res = $this->result;
1480
1481                 if ( $this->mSeekTo !== null ) {
1482                         $result = sqlsrv_fetch_array( $res, SQLSRV_FETCH_BOTH,
1483                                 SQLSRV_SCROLL_ABSOLUTE, $this->mSeekTo );
1484                         $this->mSeekTo = null;
1485                 } else {
1486                         $result = sqlsrv_fetch_array( $res );
1487                 }
1488
1489                 // MediaWiki expects us to return boolean false when there are no more rows instead of null
1490                 if ( $result === null ) {
1491                         return false;
1492                 }
1493
1494                 return $result;
1495         }
1496
1497         /**
1498          * @param int $row
1499          * @return bool
1500          */
1501         public function seek( $row ) {
1502                 $res = $this->result;
1503
1504                 // check bounds
1505                 $numRows = $this->db->numRows( $res );
1506                 $row = intval( $row );
1507
1508                 if ( $numRows === 0 ) {
1509                         return false;
1510                 } elseif ( $row < 0 || $row > $numRows - 1 ) {
1511                         return false;
1512                 }
1513
1514                 // Unlike MySQL, the seek actually happens on the next access
1515                 $this->mSeekTo = $row;
1516                 return true;
1517         }
1518 }