includes/libs/rdbms/database/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 namespace Wikimedia\Rdbms;
  29
  30 use Wikimedia;
  31 use Exception;
  32 use stdClass;
  33
  34 /**
  35  * @ingroup Database
  36  */
  37 class DatabaseMssql extends Database {
  38         /** @var int */
  39         protected $serverPort;
  40         /** @var bool */
  41         protected $useWindowsAuth = false;
  42         /** @var int|null */
  43         protected $lastInsertId = null;
  44         /** @var int|null */
  45         protected $lastAffectedRowCount = null;
  46         /** @var int */
  47         protected $subqueryId = 0;
  48         /** @var bool */
  49         protected $scrollableCursor = true;
  50         /** @var bool */
  51         protected $prepareStatements = true;
  52         /** @var stdClass[][]|null */
  53         protected $binaryColumnCache = null;
  54         /** @var stdClass[][]|null */
  55         protected $bitColumnCache = null;
  56         /** @var bool */
  57         protected $ignoreDupKeyErrors = false;
  58         /** @var string[] */
  59         protected $ignoreErrors = [];
  60
  61         public function implicitGroupby() {
  62                 return false;
  63         }
  64
  65         public function implicitOrderby() {
  66                 return false;
  67         }
  68
  69         public function unionSupportsOrderAndLimit() {
  70                 return false;
  71         }
  72
  73         public function __construct( array $params ) {
  74                 $this->serverPort = $params['port'];
  75                 $this->useWindowsAuth = $params['UseWindowsAuth'];
  76
  77                 parent::__construct( $params );
  78         }
  79
  80         /**
  81          * Usually aborts on failure
  82          * @param string $server
  83          * @param string $user
  84          * @param string $password
  85          * @param string $dbName
  86          * @throws DBConnectionError
  87          * @return bool|resource|null
  88          */
  89         public function open( $server, $user, $password, $dbName ) {
  90                 # Test for driver support, to avoid suppressed fatal error
  91                 if ( !function_exists( 'sqlsrv_connect' ) ) {
  92                         throw new DBConnectionError(
  93                                 $this,
  94                                 "Microsoft SQL Server Native (sqlsrv) functions missing.
  95                                 You can download the driver from: http://go.microsoft.com/fwlink/?LinkId=123470\n"
  96                         );
  97                 }
  98
  99                 # e.g. the class is being loaded
 100                 if ( !strlen( $user ) ) {
 101                         return null;
 102                 }
 103
 104                 $this->close();
 105                 $this->server = $server;
 106                 $this->user = $user;
 107                 $this->password = $password;
 108                 $this->dbName = $dbName;
 109
 110                 $connectionInfo = [];
 111
 112                 if ( $dbName ) {
 113                         $connectionInfo['Database'] = $dbName;
 114                 }
 115
 116                 // Decide which auth scenerio to use
 117                 // if we are using Windows auth, then don't add credentials to $connectionInfo
 118                 if ( !$this->useWindowsAuth ) {
 119                         $connectionInfo['UID'] = $user;
 120                         $connectionInfo['PWD'] = $password;
 121                 }
 122
 123                 Wikimedia\suppressWarnings();
 124                 $this->conn = sqlsrv_connect( $server, $connectionInfo );
 125                 Wikimedia\restoreWarnings();
 126
 127                 if ( $this->conn === false ) {
 128                         throw new DBConnectionError( $this, $this->lastError() );
 129                 }
 130
 131                 $this->opened = true;
 132
 133                 return $this->conn;
 134         }
 135
 136         /**
 137          * Closes a database connection, if it is open
 138          * Returns success, true if already closed
 139          * @return bool
 140          */
 141         protected function closeConnection() {
 142                 return sqlsrv_close( $this->conn );
 143         }
 144
 145         /**
 146          * @param bool|MssqlResultWrapper|resource $result
 147          * @return bool|MssqlResultWrapper
 148          */
 149         protected function resultObject( $result ) {
 150                 if ( !$result ) {
 151                         return false;
 152                 } elseif ( $result instanceof MssqlResultWrapper ) {
 153                         return $result;
 154                 } elseif ( $result === true ) {
 155                         // Successful write query
 156                         return $result;
 157                 } else {
 158                         return new MssqlResultWrapper( $this, $result );
 159                 }
 160         }
 161
 162         /**
 163          * @param string $sql
 164          * @return bool|MssqlResultWrapper|resource
 165          * @throws DBUnexpectedError
 166          */
 167         protected function doQuery( $sql ) {
 168                 // several extensions seem to think that all databases support limits
 169                 // via LIMIT N after the WHERE clause, but  MSSQL uses SELECT TOP N,
 170                 // so to catch any of those extensions we'll do a quick check for a
 171                 // LIMIT clause and pass $sql through $this->LimitToTopN() which parses
 172                 // the LIMIT clause and passes the result to $this->limitResult();
 173                 if ( preg_match( '/\bLIMIT\s*/i', $sql ) ) {
 174                         // massage LIMIT -> TopN
 175                         $sql = $this->LimitToTopN( $sql );
 176                 }
 177
 178                 // MSSQL doesn't have EXTRACT(epoch FROM XXX)
 179                 if ( preg_match( '#\bEXTRACT\s*?\(\s*?EPOCH\s+FROM\b#i', $sql, $matches ) ) {
 180                         // This is same as UNIX_TIMESTAMP, we need to calc # of seconds from 1970
 181                         $sql = str_replace( $matches[0], "DATEDIFF(s,CONVERT(datetime,'1/1/1970'),", $sql );
 182                 }
 183
 184                 // perform query
 185
 186                 // SQLSRV_CURSOR_STATIC is slower than SQLSRV_CURSOR_CLIENT_BUFFERED (one of the two is
 187                 // needed if we want to be able to seek around the result set), however CLIENT_BUFFERED
 188                 // has a bug in the sqlsrv driver where wchar_t types (such as nvarchar) that are empty
 189                 // strings make php throw a fatal error "Severe error translating Unicode"
 190                 if ( $this->scrollableCursor ) {
 191                         $scrollArr = [ 'Scrollable' => SQLSRV_CURSOR_STATIC ];
 192                 } else {
 193                         $scrollArr = [];
 194                 }
 195
 196                 if ( $this->prepareStatements ) {
 197                         // we do prepare + execute so we can get its field metadata for later usage if desired
 198                         $stmt = sqlsrv_prepare( $this->conn, $sql, [], $scrollArr );
 199                         $success = sqlsrv_execute( $stmt );
 200                 } else {
 201                         $stmt = sqlsrv_query( $this->conn, $sql, [], $scrollArr );
 202                         $success = (bool)$stmt;
 203                 }
 204
 205                 // Make a copy to ensure what we add below does not get reflected in future queries
 206                 $ignoreErrors = $this->ignoreErrors;
 207
 208                 if ( $this->ignoreDupKeyErrors ) {
 209                         // ignore duplicate key errors
 210                         // this emulates INSERT IGNORE in MySQL
 211                         $ignoreErrors[] = '2601'; // duplicate key error caused by unique index
 212                         $ignoreErrors[] = '2627'; // duplicate key error caused by primary key
 213                         $ignoreErrors[] = '3621'; // generic "the statement has been terminated" error
 214                 }
 215
 216                 if ( $success === false ) {
 217                         $errors = sqlsrv_errors();
 218                         $success = true;
 219
 220                         foreach ( $errors as $err ) {
 221                                 if ( !in_array( $err['code'], $ignoreErrors ) ) {
 222                                         $success = false;
 223                                         break;
 224                                 }
 225                         }
 226
 227                         if ( $success === false ) {
 228                                 return false;
 229                         }
 230                 }
 231                 // remember number of rows affected
 232                 $this->lastAffectedRowCount = sqlsrv_rows_affected( $stmt );
 233
 234                 return $stmt;
 235         }
 236
 237         public function freeResult( $res ) {
 238                 if ( $res instanceof ResultWrapper ) {
 239                         $res = $res->result;
 240                 }
 241
 242                 sqlsrv_free_stmt( $res );
 243         }
 244
 245         /**
 246          * @param MssqlResultWrapper $res
 247          * @return stdClass
 248          */
 249         public function fetchObject( $res ) {
 250                 // $res is expected to be an instance of MssqlResultWrapper here
 251                 return $res->fetchObject();
 252         }
 253
 254         /**
 255          * @param MssqlResultWrapper $res
 256          * @return array
 257          */
 258         public function fetchRow( $res ) {
 259                 return $res->fetchRow();
 260         }
 261
 262         /**
 263          * @param mixed $res
 264          * @return int
 265          */
 266         public function numRows( $res ) {
 267                 if ( $res instanceof ResultWrapper ) {
 268                         $res = $res->result;
 269                 }
 270
 271                 $ret = sqlsrv_num_rows( $res );
 272
 273                 if ( $ret === false ) {
 274                         // we cannot get an amount of rows from this cursor type
 275                         // has_rows returns bool true/false if the result has rows
 276                         $ret = (int)sqlsrv_has_rows( $res );
 277                 }
 278
 279                 return $ret;
 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->lastInsertId;
 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 ' .
 347                         $err['SQLSTATE'] . '][Error Code ' . $err['code'] . ']' . $err['message'];
 348         }
 349
 350         /**
 351          * @return string|int
 352          */
 353         public function lastErrno() {
 354                 $err = sqlsrv_errors( SQLSRV_ERR_ALL );
 355                 if ( $err !== null && isset( $err[0] ) ) {
 356                         return $err[0]['code'];
 357                 } else {
 358                         return 0;
 359                 }
 360         }
 361
 362         /**
 363          * @return int
 364          */
 365         protected function fetchAffectedRowCount() {
 366                 return $this->lastAffectedRowCount;
 367         }
 368
 369         /**
 370          * SELECT wrapper
 371          *
 372          * @param mixed $table Array or string, table name(s) (prefix auto-added)
 373          * @param mixed $vars Array or string, field name(s) to be retrieved
 374          * @param mixed $conds Array or string, condition(s) for WHERE
 375          * @param string $fname Calling function name (use __METHOD__) for logs/profiling
 376          * @param array $options Associative array of options (e.g.
 377          *   [ 'GROUP BY' => 'page_title' ]), see Database::makeSelectOptions
 378          *   code for list of supported stuff
 379          * @param array $join_conds Associative array of table join conditions
 380          *   (optional) (e.g. [ 'page' => [ 'LEFT JOIN','page_latest=rev_id' ] ]
 381          * @return mixed Database result resource (feed to Database::fetchObject
 382          *   or whatever), or false on failure
 383          * @throws DBQueryError
 384          * @throws DBUnexpectedError
 385          * @throws Exception
 386          */
 387         public function select( $table, $vars, $conds = '', $fname = __METHOD__,
 388                 $options = [], $join_conds = []
 389         ) {
 390                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 391                 if ( isset( $options['EXPLAIN'] ) ) {
 392                         try {
 393                                 $this->scrollableCursor = false;
 394                                 $this->prepareStatements = false;
 395                                 $this->query( "SET SHOWPLAN_ALL ON" );
 396                                 $ret = $this->query( $sql, $fname );
 397                                 $this->query( "SET SHOWPLAN_ALL OFF" );
 398                         } catch ( DBQueryError $dqe ) {
 399                                 if ( isset( $options['FOR COUNT'] ) ) {
 400                                         // likely don't have privs for SHOWPLAN, so run a select count instead
 401                                         $this->query( "SET SHOWPLAN_ALL OFF" );
 402                                         unset( $options['EXPLAIN'] );
 403                                         $ret = $this->select(
 404                                                 $table,
 405                                                 'COUNT(*) AS EstimateRows',
 406                                                 $conds,
 407                                                 $fname,
 408                                                 $options,
 409                                                 $join_conds
 410                                         );
 411                                 } else {
 412                                         // someone actually wanted the query plan instead of an est row count
 413                                         // let them know of the error
 414                                         $this->scrollableCursor = true;
 415                                         $this->prepareStatements = true;
 416                                         throw $dqe;
 417                                 }
 418                         }
 419                         $this->scrollableCursor = true;
 420                         $this->prepareStatements = true;
 421                         return $ret;
 422                 }
 423                 return $this->query( $sql, $fname );
 424         }
 425
 426         /**
 427          * SELECT wrapper
 428          *
 429          * @param mixed $table Array or string, table name(s) (prefix auto-added)
 430          * @param mixed $vars Array or string, field name(s) to be retrieved
 431          * @param mixed $conds Array or string, condition(s) for WHERE
 432          * @param string $fname Calling function name (use __METHOD__) for logs/profiling
 433          * @param array $options Associative array of options (e.g. [ 'GROUP BY' => 'page_title' ]),
 434          *   see Database::makeSelectOptions code for list of supported stuff
 435          * @param array $join_conds Associative array of table join conditions (optional)
 436          *    (e.g. [ 'page' => [ 'LEFT JOIN','page_latest=rev_id' ] ]
 437          * @return string The SQL text
 438          */
 439         public function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 440                 $options = [], $join_conds = []
 441         ) {
 442                 if ( isset( $options['EXPLAIN'] ) ) {
 443                         unset( $options['EXPLAIN'] );
 444                 }
 445
 446                 $sql = parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 447
 448                 // try to rewrite aggregations of bit columns (currently MAX and MIN)
 449                 if ( strpos( $sql, 'MAX(' ) !== false || strpos( $sql, 'MIN(' ) !== false ) {
 450                         $bitColumns = [];
 451                         if ( is_array( $table ) ) {
 452                                 $tables = $table;
 453                                 while ( $tables ) {
 454                                         $t = array_pop( $tables );
 455                                         if ( is_array( $t ) ) {
 456                                                 $tables = array_merge( $tables, $t );
 457                                         } else {
 458                                                 $bitColumns += $this->getBitColumns( $this->tableName( $t ) );
 459                                         }
 460                                 }
 461                         } else {
 462                                 $bitColumns = $this->getBitColumns( $this->tableName( $table ) );
 463                         }
 464
 465                         foreach ( $bitColumns as $col => $info ) {
 466                                 $replace = [
 467                                         "MAX({$col})" => "MAX(CAST({$col} AS tinyint))",
 468                                         "MIN({$col})" => "MIN(CAST({$col} AS tinyint))",
 469                                 ];
 470                                 $sql = str_replace( array_keys( $replace ), array_values( $replace ), $sql );
 471                         }
 472                 }
 473
 474                 return $sql;
 475         }
 476
 477         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
 478                 $fname = __METHOD__
 479         ) {
 480                 $this->scrollableCursor = false;
 481                 try {
 482                         parent::deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname );
 483                 } catch ( Exception $e ) {
 484                         $this->scrollableCursor = true;
 485                         throw $e;
 486                 }
 487                 $this->scrollableCursor = true;
 488         }
 489
 490         public function delete( $table, $conds, $fname = __METHOD__ ) {
 491                 $this->scrollableCursor = false;
 492                 try {
 493                         parent::delete( $table, $conds, $fname );
 494                 } catch ( Exception $e ) {
 495                         $this->scrollableCursor = true;
 496                         throw $e;
 497                 }
 498                 $this->scrollableCursor = true;
 499         }
 500
 501         /**
 502          * Estimate rows in dataset
 503          * Returns estimated count, based on SHOWPLAN_ALL output
 504          * This is not necessarily an accurate estimate, so use sparingly
 505          * Returns -1 if count cannot be found
 506          * Takes same arguments as Database::select()
 507          * @param string $table
 508          * @param string $var
 509          * @param string $conds
 510          * @param string $fname
 511          * @param array $options
 512          * @param array $join_conds
 513          * @return int
 514          */
 515         public function estimateRowCount( $table, $var = '*', $conds = '',
 516                 $fname = __METHOD__, $options = [], $join_conds = []
 517         ) {
 518                 $conds = $this->normalizeConditions( $conds, $fname );
 519                 $column = $this->extractSingleFieldFromList( $var );
 520                 if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
 521                         $conds[] = "$column IS NOT NULL";
 522                 }
 523
 524                 // http://msdn2.microsoft.com/en-us/library/aa259203.aspx
 525                 $options['EXPLAIN'] = true;
 526                 $options['FOR COUNT'] = true;
 527                 $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
 528
 529                 $rows = -1;
 530                 if ( $res ) {
 531                         $row = $this->fetchRow( $res );
 532
 533                         if ( isset( $row['EstimateRows'] ) ) {
 534                                 $rows = (int)$row['EstimateRows'];
 535                         }
 536                 }
 537
 538                 return $rows;
 539         }
 540
 541         /**
 542          * Returns information about an index
 543          * If errors are explicitly ignored, returns NULL on failure
 544          * @param string $table
 545          * @param string $index
 546          * @param string $fname
 547          * @return array|bool|null
 548          */
 549         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 550                 # This does not return the same info as MYSQL would, but that's OK
 551                 # because MediaWiki never uses the returned value except to check for
 552                 # the existence of indexes.
 553                 $sql = "sp_helpindex '" . $this->tableName( $table ) . "'";
 554                 $res = $this->query( $sql, $fname );
 555
 556                 if ( !$res ) {
 557                         return null;
 558                 }
 559
 560                 $result = [];
 561                 foreach ( $res as $row ) {
 562                         if ( $row->index_name == $index ) {
 563                                 $row->Non_unique = !stristr( $row->index_description, "unique" );
 564                                 $cols = explode( ", ", $row->index_keys );
 565                                 foreach ( $cols as $col ) {
 566                                         $row->Column_name = trim( $col );
 567                                         $result[] = clone $row;
 568                                 }
 569                         } elseif ( $index == 'PRIMARY' && stristr( $row->index_description, 'PRIMARY' ) ) {
 570                                 $row->Non_unique = 0;
 571                                 $cols = explode( ", ", $row->index_keys );
 572                                 foreach ( $cols as $col ) {
 573                                         $row->Column_name = trim( $col );
 574                                         $result[] = clone $row;
 575                                 }
 576                         }
 577                 }
 578
 579                 return $result ?: false;
 580         }
 581
 582         /**
 583          * INSERT wrapper, inserts an array into a table
 584          *
 585          * $arrToInsert may be a single associative array, or an array of these with numeric keys, for
 586          * multi-row insert.
 587          *
 588          * Usually aborts on failure
 589          * If errors are explicitly ignored, returns success
 590          * @param string $table
 591          * @param array $arrToInsert
 592          * @param string $fname
 593          * @param array $options
 594          * @return bool
 595          * @throws Exception
 596          */
 597         public function insert( $table, $arrToInsert, $fname = __METHOD__, $options = [] ) {
 598                 # No rows to insert, easy just return now
 599                 if ( !count( $arrToInsert ) ) {
 600                         return true;
 601                 }
 602
 603                 if ( !is_array( $options ) ) {
 604                         $options = [ $options ];
 605                 }
 606
 607                 $table = $this->tableName( $table );
 608
 609                 if ( !( isset( $arrToInsert[0] ) && is_array( $arrToInsert[0] ) ) ) { // Not multi row
 610                         $arrToInsert = [ 0 => $arrToInsert ]; // make everything multi row compatible
 611                 }
 612
 613                 // We know the table we're inserting into, get its identity column
 614                 $identity = null;
 615                 // strip matching square brackets and the db/schema from table name
 616                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
 617                 $tableRaw = array_pop( $tableRawArr );
 618                 $res = $this->doQuery(
 619                         "SELECT NAME AS idColumn FROM SYS.IDENTITY_COLUMNS " .
 620                                 "WHERE OBJECT_NAME(OBJECT_ID)='{$tableRaw}'"
 621                 );
 622                 if ( $res && sqlsrv_has_rows( $res ) ) {
 623                         // There is an identity for this table.
 624                         $identityArr = sqlsrv_fetch_array( $res, SQLSRV_FETCH_ASSOC );
 625                         $identity = array_pop( $identityArr );
 626                 }
 627                 sqlsrv_free_stmt( $res );
 628
 629                 // Determine binary/varbinary fields so we can encode data as a hex string like 0xABCDEF
 630                 $binaryColumns = $this->getBinaryColumns( $table );
 631
 632                 // INSERT IGNORE is not supported by SQL Server
 633                 // remove IGNORE from options list and set ignore flag to true
 634                 if ( in_array( 'IGNORE', $options ) ) {
 635                         $options = array_diff( $options, [ 'IGNORE' ] );
 636                         $this->ignoreDupKeyErrors = true;
 637                 }
 638
 639                 $ret = null;
 640                 foreach ( $arrToInsert as $a ) {
 641                         // start out with empty identity column, this is so we can return
 642                         // it as a result of the INSERT logic
 643                         $sqlPre = '';
 644                         $sqlPost = '';
 645                         $identityClause = '';
 646
 647                         // if we have an identity column
 648                         if ( $identity ) {
 649                                 // iterate through
 650                                 foreach ( $a as $k => $v ) {
 651                                         if ( $k == $identity ) {
 652                                                 if ( !is_null( $v ) ) {
 653                                                         // there is a value being passed to us,
 654                                                         // we need to turn on and off inserted identity
 655                                                         $sqlPre = "SET IDENTITY_INSERT $table ON;";
 656                                                         $sqlPost = ";SET IDENTITY_INSERT $table OFF;";
 657                                                 } else {
 658                                                         // we can't insert NULL into an identity column,
 659                                                         // so remove the column from the insert.
 660                                                         unset( $a[$k] );
 661                                                 }
 662                                         }
 663                                 }
 664
 665                                 // we want to output an identity column as result
 666                                 $identityClause = "OUTPUT INSERTED.$identity ";
 667                         }
 668
 669                         $keys = array_keys( $a );
 670
 671                         // Build the actual query
 672                         $sql = $sqlPre . 'INSERT ' . implode( ' ', $options ) .
 673                                 " INTO $table (" . implode( ',', $keys ) . ") $identityClause VALUES (";
 674
 675                         $first = true;
 676                         foreach ( $a as $key => $value ) {
 677                                 if ( isset( $binaryColumns[$key] ) ) {
 678                                         $value = new MssqlBlob( $value );
 679                                 }
 680                                 if ( $first ) {
 681                                         $first = false;
 682                                 } else {
 683                                         $sql .= ',';
 684                                 }
 685                                 if ( is_null( $value ) ) {
 686                                         $sql .= 'null';
 687                                 } elseif ( is_array( $value ) || is_object( $value ) ) {
 688                                         if ( is_object( $value ) && $value instanceof Blob ) {
 689                                                 $sql .= $this->addQuotes( $value );
 690                                         } else {
 691                                                 $sql .= $this->addQuotes( serialize( $value ) );
 692                                         }
 693                                 } else {
 694                                         $sql .= $this->addQuotes( $value );
 695                                 }
 696                         }
 697                         $sql .= ')' . $sqlPost;
 698
 699                         // Run the query
 700                         $this->scrollableCursor = false;
 701                         try {
 702                                 $ret = $this->query( $sql );
 703                         } catch ( Exception $e ) {
 704                                 $this->scrollableCursor = true;
 705                                 $this->ignoreDupKeyErrors = false;
 706                                 throw $e;
 707                         }
 708                         $this->scrollableCursor = true;
 709
 710                         if ( $ret instanceof ResultWrapper && !is_null( $identity ) ) {
 711                                 // Then we want to get the identity column value we were assigned and save it off
 712                                 $row = $ret->fetchObject();
 713                                 if ( is_object( $row ) ) {
 714                                         $this->lastInsertId = $row->$identity;
 715                                         // It seems that mAffectedRows is -1 sometimes when OUTPUT INSERTED.identity is
 716                                         // used if we got an identity back, we know for sure a row was affected, so
 717                                         // adjust that here
 718                                         if ( $this->lastAffectedRowCount == -1 ) {
 719                                                 $this->lastAffectedRowCount = 1;
 720                                         }
 721                                 }
 722                         }
 723                 }
 724
 725                 $this->ignoreDupKeyErrors = false;
 726
 727                 return $ret;
 728         }
 729
 730         /**
 731          * INSERT SELECT wrapper
 732          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 733          * Source items may be literals rather than field names, but strings should
 734          * be quoted with Database::addQuotes().
 735          * @param string $destTable
 736          * @param array|string $srcTable May be an array of tables.
 737          * @param array $varMap
 738          * @param array $conds May be "*" to copy the whole table.
 739          * @param string $fname
 740          * @param array $insertOptions
 741          * @param array $selectOptions
 742          * @param array $selectJoinConds
 743          * @return bool
 744          * @throws Exception
 745          */
 746         public function nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 747                 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
 748         ) {
 749                 $this->scrollableCursor = false;
 750                 try {
 751                         $ret = parent::nativeInsertSelect(
 752                                 $destTable,
 753                                 $srcTable,
 754                                 $varMap,
 755                                 $conds,
 756                                 $fname,
 757                                 $insertOptions,
 758                                 $selectOptions,
 759                                 $selectJoinConds
 760                         );
 761                 } catch ( Exception $e ) {
 762                         $this->scrollableCursor = true;
 763                         throw $e;
 764                 }
 765                 $this->scrollableCursor = true;
 766
 767                 return $ret;
 768         }
 769
 770         /**
 771          * UPDATE wrapper. Takes a condition array and a SET array.
 772          *
 773          * @param string $table Name of the table to UPDATE. This will be passed through
 774          *                Database::tableName().
 775          *
 776          * @param array $values An array of values to SET. For each array element,
 777          *                the key gives the field name, and the value gives the data
 778          *                to set that field to. The data will be quoted by
 779          *                Database::addQuotes().
 780          *
 781          * @param array $conds An array of conditions (WHERE). See
 782          *                Database::select() for the details of the format of
 783          *                condition arrays. Use '*' to update all rows.
 784          *
 785          * @param string $fname The function name of the caller (from __METHOD__),
 786          *                for logging and profiling.
 787          *
 788          * @param array $options An array of UPDATE options, can be:
 789          *                   - IGNORE: Ignore unique key conflicts
 790          *                   - LOW_PRIORITY: MySQL-specific, see MySQL manual.
 791          * @return bool
 792          * @throws DBUnexpectedError
 793          * @throws Exception
 794          */
 795         function update( $table, $values, $conds, $fname = __METHOD__, $options = [] ) {
 796                 $table = $this->tableName( $table );
 797                 $binaryColumns = $this->getBinaryColumns( $table );
 798
 799                 $opts = $this->makeUpdateOptions( $options );
 800                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET, $binaryColumns );
 801
 802                 if ( $conds !== [] && $conds !== '*' ) {
 803                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND, $binaryColumns );
 804                 }
 805
 806                 $this->scrollableCursor = false;
 807                 try {
 808                         $this->query( $sql );
 809                 } catch ( Exception $e ) {
 810                         $this->scrollableCursor = true;
 811                         throw $e;
 812                 }
 813                 $this->scrollableCursor = true;
 814                 return true;
 815         }
 816
 817         /**
 818          * Makes an encoded list of strings from an array
 819          * @param array $a Containing the data
 820          * @param int $mode Constant
 821          *      - LIST_COMMA:          comma separated, no field names
 822          *      - LIST_AND:            ANDed WHERE clause (without the WHERE). See
 823          *        the documentation for $conds in Database::select().
 824          *      - LIST_OR:             ORed WHERE clause (without the WHERE)
 825          *      - LIST_SET:            comma separated with field names, like a SET clause
 826          *      - LIST_NAMES:          comma separated field names
 827          * @param array $binaryColumns Contains a list of column names that are binary types
 828          *      This is a custom parameter only present for MS SQL.
 829          *
 830          * @throws DBUnexpectedError
 831          * @return string
 832          */
 833         public function makeList( $a, $mode = LIST_COMMA, $binaryColumns = [] ) {
 834                 if ( !is_array( $a ) ) {
 835                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with incorrect parameters' );
 836                 }
 837
 838                 if ( $mode != LIST_NAMES ) {
 839                         // In MS SQL, values need to be specially encoded when they are
 840                         // inserted into binary fields. Perform this necessary encoding
 841                         // for the specified set of columns.
 842                         foreach ( array_keys( $a ) as $field ) {
 843                                 if ( !isset( $binaryColumns[$field] ) ) {
 844                                         continue;
 845                                 }
 846
 847                                 if ( is_array( $a[$field] ) ) {
 848                                         foreach ( $a[$field] as &$v ) {
 849                                                 $v = new MssqlBlob( $v );
 850                                         }
 851                                         unset( $v );
 852                                 } else {
 853                                         $a[$field] = new MssqlBlob( $a[$field] );
 854                                 }
 855                         }
 856                 }
 857
 858                 return parent::makeList( $a, $mode );
 859         }
 860
 861         /**
 862          * @param string $table
 863          * @param string $field
 864          * @return int Returns the size of a text field, or -1 for "unlimited"
 865          */
 866         public function textFieldSize( $table, $field ) {
 867                 $table = $this->tableName( $table );
 868                 $sql = "SELECT CHARACTER_MAXIMUM_LENGTH,DATA_TYPE FROM INFORMATION_SCHEMA.Columns
 869                         WHERE TABLE_NAME = '$table' AND COLUMN_NAME = '$field'";
 870                 $res = $this->query( $sql );
 871                 $row = $this->fetchRow( $res );
 872                 $size = -1;
 873                 if ( strtolower( $row['DATA_TYPE'] ) != 'text' ) {
 874                         $size = $row['CHARACTER_MAXIMUM_LENGTH'];
 875                 }
 876
 877                 return $size;
 878         }
 879
 880         /**
 881          * Construct a LIMIT query with optional offset
 882          * This is used for query pages
 883          *
 884          * @param string $sql SQL query we will append the limit too
 885          * @param int $limit The SQL limit
 886          * @param bool|int $offset The SQL offset (default false)
 887          * @return array|string
 888          * @throws DBUnexpectedError
 889          */
 890         public function limitResult( $sql, $limit, $offset = false ) {
 891                 if ( $offset === false || $offset == 0 ) {
 892                         if ( strpos( $sql, "SELECT" ) === false ) {
 893                                 return "TOP {$limit} " . $sql;
 894                         } else {
 895                                 return preg_replace( '/\bSELECT(\s+DISTINCT)?\b/Dsi',
 896                                         'SELECT$1 TOP ' . $limit, $sql, 1 );
 897                         }
 898                 } else {
 899                         // This one is fun, we need to pull out the select list as well as any ORDER BY clause
 900                         $select = $orderby = [];
 901                         $s1 = preg_match( '#SELECT\s+(.+?)\s+FROM#Dis', $sql, $select );
 902                         $s2 = preg_match( '#(ORDER BY\s+.+?)(\s*FOR XML .*)?$#Dis', $sql, $orderby );
 903                         $postOrder = '';
 904                         $first = $offset + 1;
 905                         $last = $offset + $limit;
 906                         $sub1 = 'sub_' . $this->subqueryId;
 907                         $sub2 = 'sub_' . ( $this->subqueryId + 1 );
 908                         $this->subqueryId += 2;
 909                         if ( !$s1 ) {
 910                                 // wat
 911                                 throw new DBUnexpectedError( $this, "Attempting to LIMIT a non-SELECT query\n" );
 912                         }
 913                         if ( !$s2 ) {
 914                                 // no ORDER BY
 915                                 $overOrder = 'ORDER BY (SELECT 1)';
 916                         } else {
 917                                 if ( !isset( $orderby[2] ) || !$orderby[2] ) {
 918                                         // don't need to strip it out if we're using a FOR XML clause
 919                                         $sql = str_replace( $orderby[1], '', $sql );
 920                                 }
 921                                 $overOrder = $orderby[1];
 922                                 $postOrder = ' ' . $overOrder;
 923                         }
 924                         $sql = "SELECT {$select[1]}
 925                                         FROM (
 926                                                 SELECT ROW_NUMBER() OVER({$overOrder}) AS rowNumber, *
 927                                                 FROM ({$sql}) {$sub1}
 928                                         ) {$sub2}
 929                                         WHERE rowNumber BETWEEN {$first} AND {$last}{$postOrder}";
 930
 931                         return $sql;
 932                 }
 933         }
 934
 935         /**
 936          * If there is a limit clause, parse it, strip it, and pass the remaining
 937          * SQL through limitResult() with the appropriate parameters. Not the
 938          * prettiest solution, but better than building a whole new parser. This
 939          * exists becase there are still too many extensions that don't use dynamic
 940          * sql generation.
 941          *
 942          * @param string $sql
 943          * @return array|mixed|string
 944          */
 945         public function LimitToTopN( $sql ) {
 946                 // Matches: LIMIT {[offset,] row_count | row_count OFFSET offset}
 947                 $pattern = '/\bLIMIT\s+((([0-9]+)\s*,\s*)?([0-9]+)(\s+OFFSET\s+([0-9]+))?)/i';
 948                 if ( preg_match( $pattern, $sql, $matches ) ) {
 949                         $row_count = $matches[4];
 950                         $offset = $matches[3] ?: $matches[6] ?: false;
 951
 952                         // strip the matching LIMIT clause out
 953                         $sql = str_replace( $matches[0], '', $sql );
 954
 955                         return $this->limitResult( $sql, $row_count, $offset );
 956                 }
 957
 958                 return $sql;
 959         }
 960
 961         /**
 962          * @return string Wikitext of a link to the server software's web site
 963          */
 964         public function getSoftwareLink() {
 965                 return "[{{int:version-db-mssql-url}} MS SQL Server]";
 966         }
 967
 968         /**
 969          * @return string Version information from the database
 970          */
 971         public function getServerVersion() {
 972                 $server_info = sqlsrv_server_info( $this->conn );
 973                 $version = 'Error';
 974                 if ( isset( $server_info['SQLServerVersion'] ) ) {
 975                         $version = $server_info['SQLServerVersion'];
 976                 }
 977
 978                 return $version;
 979         }
 980
 981         /**
 982          * @param string $table
 983          * @param string $fname
 984          * @return bool
 985          */
 986         public function tableExists( $table, $fname = __METHOD__ ) {
 987                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
 988
 989                 if ( $db !== false ) {
 990                         // remote database
 991                         $this->queryLogger->error( "Attempting to call tableExists on a remote table" );
 992                         return false;
 993                 }
 994
 995                 if ( $schema === false ) {
 996                         $schema = $this->schema;
 997                 }
 998
 999                 $res = $this->query( "SELECT 1 FROM INFORMATION_SCHEMA.TABLES
1000                         WHERE TABLE_TYPE = 'BASE TABLE'
1001                         AND TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table'" );
1002
1003                 if ( $res->numRows() ) {
1004                         return true;
1005                 } else {
1006                         return false;
1007                 }
1008         }
1009
1010         /**
1011          * Query whether a given column exists in the mediawiki schema
1012          * @param string $table
1013          * @param string $field
1014          * @param string $fname
1015          * @return bool
1016          */
1017         public function fieldExists( $table, $field, $fname = __METHOD__ ) {
1018                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
1019
1020                 if ( $db !== false ) {
1021                         // remote database
1022                         $this->queryLogger->error( "Attempting to call fieldExists on a remote table" );
1023                         return false;
1024                 }
1025
1026                 $res = $this->query( "SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS
1027                         WHERE TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table' AND COLUMN_NAME = '$field'" );
1028
1029                 if ( $res->numRows() ) {
1030                         return true;
1031                 } else {
1032                         return false;
1033                 }
1034         }
1035
1036         public function fieldInfo( $table, $field ) {
1037                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
1038
1039                 if ( $db !== false ) {
1040                         // remote database
1041                         $this->queryLogger->error( "Attempting to call fieldInfo on a remote table" );
1042                         return false;
1043                 }
1044
1045                 $res = $this->query( "SELECT * FROM INFORMATION_SCHEMA.COLUMNS
1046                         WHERE TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table' AND COLUMN_NAME = '$field'" );
1047
1048                 $meta = $res->fetchRow();
1049                 if ( $meta ) {
1050                         return new MssqlField( $meta );
1051                 }
1052
1053                 return false;
1054         }
1055
1056         /**
1057          * Begin a transaction, committing any previously open transaction
1058          * @param string $fname
1059          */
1060         protected function doBegin( $fname = __METHOD__ ) {
1061                 sqlsrv_begin_transaction( $this->conn );
1062                 $this->trxLevel = 1;
1063         }
1064
1065         /**
1066          * End a transaction
1067          * @param string $fname
1068          */
1069         protected function doCommit( $fname = __METHOD__ ) {
1070                 sqlsrv_commit( $this->conn );
1071                 $this->trxLevel = 0;
1072         }
1073
1074         /**
1075          * Rollback a transaction.
1076          * No-op on non-transactional databases.
1077          * @param string $fname
1078          */
1079         protected function doRollback( $fname = __METHOD__ ) {
1080                 sqlsrv_rollback( $this->conn );
1081                 $this->trxLevel = 0;
1082         }
1083
1084         /**
1085          * @param string $s
1086          * @return string
1087          */
1088         public function strencode( $s ) {
1089                 // Should not be called by us
1090                 return str_replace( "'", "''", $s );
1091         }
1092
1093         /**
1094          * @param string|int|null|bool|Blob $s
1095          * @return string|int
1096          */
1097         public function addQuotes( $s ) {
1098                 if ( $s instanceof MssqlBlob ) {
1099                         return $s->fetch();
1100                 } elseif ( $s instanceof Blob ) {
1101                         // this shouldn't really ever be called, but it's here if needed
1102                         // (and will quite possibly make the SQL error out)
1103                         $blob = new MssqlBlob( $s->fetch() );
1104                         return $blob->fetch();
1105                 } else {
1106                         if ( is_bool( $s ) ) {
1107                                 $s = $s ? 1 : 0;
1108                         }
1109                         return parent::addQuotes( $s );
1110                 }
1111         }
1112
1113         /**
1114          * @param string $s
1115          * @return string
1116          */
1117         public function addIdentifierQuotes( $s ) {
1118                 // http://msdn.microsoft.com/en-us/library/aa223962.aspx
1119                 return '[' . $s . ']';
1120         }
1121
1122         /**
1123          * @param string $name
1124          * @return bool
1125          */
1126         public function isQuotedIdentifier( $name ) {
1127                 return strlen( $name ) && $name[0] == '[' && substr( $name, -1, 1 ) == ']';
1128         }
1129
1130         /**
1131          * MS SQL supports more pattern operators than other databases (ex: [,],^)
1132          *
1133          * @param string $s
1134          * @param string $escapeChar
1135          * @return string
1136          */
1137         protected function escapeLikeInternal( $s, $escapeChar = '`' ) {
1138                 return str_replace( [ $escapeChar, '%', '_', '[', ']', '^' ],
1139                         [ "{$escapeChar}{$escapeChar}", "{$escapeChar}%", "{$escapeChar}_",
1140                                 "{$escapeChar}[", "{$escapeChar}]", "{$escapeChar}^" ],
1141                         $s );
1142         }
1143
1144         /**
1145          * @param string $db
1146          * @return bool
1147          */
1148         public function selectDB( $db ) {
1149                 try {
1150                         $this->dbName = $db;
1151                         $this->query( "USE $db" );
1152                         return true;
1153                 } catch ( Exception $e ) {
1154                         return false;
1155                 }
1156         }
1157
1158         /**
1159          * @param array $options An associative array of options to be turned into
1160          *   an SQL query, valid keys are listed in the function.
1161          * @return array
1162          */
1163         public function makeSelectOptions( $options ) {
1164                 $tailOpts = '';
1165                 $startOpts = '';
1166
1167                 $noKeyOptions = [];
1168                 foreach ( $options as $key => $option ) {
1169                         if ( is_numeric( $key ) ) {
1170                                 $noKeyOptions[$option] = true;
1171                         }
1172                 }
1173
1174                 $tailOpts .= $this->makeGroupByWithHaving( $options );
1175
1176                 $tailOpts .= $this->makeOrderBy( $options );
1177
1178                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1179                         $startOpts .= 'DISTINCT';
1180                 }
1181
1182                 if ( isset( $noKeyOptions['FOR XML'] ) ) {
1183                         // used in group concat field emulation
1184                         $tailOpts .= " FOR XML PATH('')";
1185                 }
1186
1187                 // we want this to be compatible with the output of parent::makeSelectOptions()
1188                 return [ $startOpts, '', $tailOpts, '', '' ];
1189         }
1190
1191         public function getType() {
1192                 return 'mssql';
1193         }
1194
1195         /**
1196          * @param array $stringList
1197          * @return string
1198          */
1199         public function buildConcat( $stringList ) {
1200                 return implode( ' + ', $stringList );
1201         }
1202
1203         /**
1204          * Build a GROUP_CONCAT or equivalent statement for a query.
1205          * MS SQL doesn't have GROUP_CONCAT so we emulate it with other stuff (and boy is it nasty)
1206          *
1207          * This is useful for combining a field for several rows into a single string.
1208          * NULL values will not appear in the output, duplicated values will appear,
1209          * and the resulting delimiter-separated values have no defined sort order.
1210          * Code using the results may need to use the PHP unique() or sort() methods.
1211          *
1212          * @param string $delim Glue to bind the results together
1213          * @param string|array $table Table name
1214          * @param string $field Field name
1215          * @param string|array $conds Conditions
1216          * @param string|array $join_conds Join conditions
1217          * @return string SQL text
1218          * @since 1.23
1219          */
1220         public function buildGroupConcatField( $delim, $table, $field, $conds = '',
1221                 $join_conds = []
1222         ) {
1223                 $gcsq = 'gcsq_' . $this->subqueryId;
1224                 $this->subqueryId++;
1225
1226                 $delimLen = strlen( $delim );
1227                 $fld = "{$field} + {$this->addQuotes( $delim )}";
1228                 $sql = "(SELECT LEFT({$field}, LEN({$field}) - {$delimLen}) FROM ("
1229                         . $this->selectSQLText( $table, $fld, $conds, null, [ 'FOR XML' ], $join_conds )
1230                         . ") {$gcsq} ({$field}))";
1231
1232                 return $sql;
1233         }
1234
1235         public function buildSubstring( $input, $startPosition, $length = null ) {
1236                 $this->assertBuildSubstringParams( $startPosition, $length );
1237                 if ( $length === null ) {
1238                         /**
1239                          * MSSQL doesn't allow an empty length parameter, so when we don't want to limit the
1240                          * length returned use the default maximum size of text.
1241                          * @see https://docs.microsoft.com/en-us/sql/t-sql/statements/set-textsize-transact-sql
1242                          */
1243                         $length = 2147483647;
1244                 }
1245                 return 'SUBSTRING(' . implode( ',', [ $input, $startPosition, $length ] ) . ')';
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->binaryColumnCache === null ) {
1259                         $this->populateColumnCaches();
1260                 }
1261
1262                 return isset( $this->binaryColumnCache[$tableRaw] )
1263                         ? $this->binaryColumnCache[$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->bitColumnCache === null ) {
1276                         $this->populateColumnCaches();
1277                 }
1278
1279                 return isset( $this->bitColumnCache[$tableRaw] )
1280                         ? $this->bitColumnCache[$tableRaw]
1281                         : [];
1282         }
1283
1284         private function populateColumnCaches() {
1285                 $res = $this->select( 'INFORMATION_SCHEMA.COLUMNS', '*',
1286                         [
1287                                 'TABLE_CATALOG' => $this->dbName,
1288                                 'TABLE_SCHEMA' => $this->schema,
1289                                 'DATA_TYPE' => [ 'varbinary', 'binary', 'image', 'bit' ]
1290                         ] );
1291
1292                 $this->binaryColumnCache = [];
1293                 $this->bitColumnCache = [];
1294                 foreach ( $res as $row ) {
1295                         if ( $row->DATA_TYPE == 'bit' ) {
1296                                 $this->bitColumnCache[$row->TABLE_NAME][$row->COLUMN_NAME] = $row;
1297                         } else {
1298                                 $this->binaryColumnCache[$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                 $old = $this->prepareStatements;
1363                 if ( $value !== null ) {
1364                         $this->prepareStatements = $value;
1365                 }
1366
1367                 return $old;
1368         }
1369
1370         /**
1371          * Called in the installer and updater.
1372          * Probably doesn't need to be called anywhere else in the codebase.
1373          * @param bool|null $value
1374          * @return bool|null
1375          */
1376         public function scrollableCursor( $value = null ) {
1377                 $old = $this->scrollableCursor;
1378                 if ( $value !== null ) {
1379                         $this->scrollableCursor = $value;
1380                 }
1381
1382                 return $old;
1383         }
1384 }
1385
1386 class_alias( DatabaseMssql::class, 'DatabaseMssql' );