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         protected function open( $server, $user, $password, $dbName ) {
  81                 # Test for driver support, to avoid suppressed fatal error
  82                 if ( !function_exists( 'sqlsrv_connect' ) ) {
  83                         throw new DBConnectionError(
  84                                 $this,
  85                                 "Microsoft SQL Server Native (sqlsrv) functions missing.
  86                                 You can download the driver from: http://go.microsoft.com/fwlink/?LinkId=123470\n"
  87                         );
  88                 }
  89
  90                 # e.g. the class is being loaded
  91                 if ( !strlen( $user ) ) {
  92                         return null;
  93                 }
  94
  95                 $this->close();
  96                 $this->server = $server;
  97                 $this->user = $user;
  98                 $this->password = $password;
  99                 $this->dbName = $dbName;
 100
 101                 $connectionInfo = [];
 102
 103                 if ( $dbName ) {
 104                         $connectionInfo['Database'] = $dbName;
 105                 }
 106
 107                 // Decide which auth scenerio to use
 108                 // if we are using Windows auth, then don't add credentials to $connectionInfo
 109                 if ( !$this->useWindowsAuth ) {
 110                         $connectionInfo['UID'] = $user;
 111                         $connectionInfo['PWD'] = $password;
 112                 }
 113
 114                 Wikimedia\suppressWarnings();
 115                 $this->conn = sqlsrv_connect( $server, $connectionInfo );
 116                 Wikimedia\restoreWarnings();
 117
 118                 if ( $this->conn === false ) {
 119                         throw new DBConnectionError( $this, $this->lastError() );
 120                 }
 121
 122                 $this->opened = true;
 123
 124                 return (bool)$this->conn;
 125         }
 126
 127         /**
 128          * Closes a database connection, if it is open
 129          * Returns success, true if already closed
 130          * @return bool
 131          */
 132         protected function closeConnection() {
 133                 return sqlsrv_close( $this->conn );
 134         }
 135
 136         /**
 137          * @param bool|MssqlResultWrapper|resource $result
 138          * @return bool|MssqlResultWrapper
 139          */
 140         protected function resultObject( $result ) {
 141                 if ( !$result ) {
 142                         return false;
 143                 } elseif ( $result instanceof MssqlResultWrapper ) {
 144                         return $result;
 145                 } elseif ( $result === true ) {
 146                         // Successful write query
 147                         return $result;
 148                 } else {
 149                         return new MssqlResultWrapper( $this, $result );
 150                 }
 151         }
 152
 153         /**
 154          * @param string $sql
 155          * @return bool|MssqlResultWrapper|resource
 156          * @throws DBUnexpectedError
 157          */
 158         protected function doQuery( $sql ) {
 159                 // several extensions seem to think that all databases support limits
 160                 // via LIMIT N after the WHERE clause, but  MSSQL uses SELECT TOP N,
 161                 // so to catch any of those extensions we'll do a quick check for a
 162                 // LIMIT clause and pass $sql through $this->LimitToTopN() which parses
 163                 // the LIMIT clause and passes the result to $this->limitResult();
 164                 if ( preg_match( '/\bLIMIT\s*/i', $sql ) ) {
 165                         // massage LIMIT -> TopN
 166                         $sql = $this->LimitToTopN( $sql );
 167                 }
 168
 169                 // MSSQL doesn't have EXTRACT(epoch FROM XXX)
 170                 if ( preg_match( '#\bEXTRACT\s*?\(\s*?EPOCH\s+FROM\b#i', $sql, $matches ) ) {
 171                         // This is same as UNIX_TIMESTAMP, we need to calc # of seconds from 1970
 172                         $sql = str_replace( $matches[0], "DATEDIFF(s,CONVERT(datetime,'1/1/1970'),", $sql );
 173                 }
 174
 175                 // perform query
 176
 177                 // SQLSRV_CURSOR_STATIC is slower than SQLSRV_CURSOR_CLIENT_BUFFERED (one of the two is
 178                 // needed if we want to be able to seek around the result set), however CLIENT_BUFFERED
 179                 // has a bug in the sqlsrv driver where wchar_t types (such as nvarchar) that are empty
 180                 // strings make php throw a fatal error "Severe error translating Unicode"
 181                 if ( $this->scrollableCursor ) {
 182                         $scrollArr = [ 'Scrollable' => SQLSRV_CURSOR_STATIC ];
 183                 } else {
 184                         $scrollArr = [];
 185                 }
 186
 187                 if ( $this->prepareStatements ) {
 188                         // we do prepare + execute so we can get its field metadata for later usage if desired
 189                         $stmt = sqlsrv_prepare( $this->conn, $sql, [], $scrollArr );
 190                         $success = sqlsrv_execute( $stmt );
 191                 } else {
 192                         $stmt = sqlsrv_query( $this->conn, $sql, [], $scrollArr );
 193                         $success = (bool)$stmt;
 194                 }
 195
 196                 // Make a copy to ensure what we add below does not get reflected in future queries
 197                 $ignoreErrors = $this->ignoreErrors;
 198
 199                 if ( $this->ignoreDupKeyErrors ) {
 200                         // ignore duplicate key errors
 201                         // this emulates INSERT IGNORE in MySQL
 202                         $ignoreErrors[] = '2601'; // duplicate key error caused by unique index
 203                         $ignoreErrors[] = '2627'; // duplicate key error caused by primary key
 204                         $ignoreErrors[] = '3621'; // generic "the statement has been terminated" error
 205                 }
 206
 207                 if ( $success === false ) {
 208                         $errors = sqlsrv_errors();
 209                         $success = true;
 210
 211                         foreach ( $errors as $err ) {
 212                                 if ( !in_array( $err['code'], $ignoreErrors ) ) {
 213                                         $success = false;
 214                                         break;
 215                                 }
 216                         }
 217
 218                         if ( $success === false ) {
 219                                 return false;
 220                         }
 221                 }
 222                 // remember number of rows affected
 223                 $this->lastAffectedRowCount = sqlsrv_rows_affected( $stmt );
 224
 225                 return $stmt;
 226         }
 227
 228         public function freeResult( $res ) {
 229                 if ( $res instanceof ResultWrapper ) {
 230                         $res = $res->result;
 231                 }
 232
 233                 sqlsrv_free_stmt( $res );
 234         }
 235
 236         /**
 237          * @param IResultWrapper $res
 238          * @return stdClass
 239          */
 240         public function fetchObject( $res ) {
 241                 // $res is expected to be an instance of MssqlResultWrapper here
 242                 return $res->fetchObject();
 243         }
 244
 245         /**
 246          * @param IResultWrapper $res
 247          * @return array
 248          */
 249         public function fetchRow( $res ) {
 250                 return $res->fetchRow();
 251         }
 252
 253         /**
 254          * @param mixed $res
 255          * @return int
 256          */
 257         public function numRows( $res ) {
 258                 if ( $res instanceof ResultWrapper ) {
 259                         $res = $res->result;
 260                 }
 261
 262                 $ret = sqlsrv_num_rows( $res );
 263
 264                 if ( $ret === false ) {
 265                         // we cannot get an amount of rows from this cursor type
 266                         // has_rows returns bool true/false if the result has rows
 267                         $ret = (int)sqlsrv_has_rows( $res );
 268                 }
 269
 270                 return $ret;
 271         }
 272
 273         /**
 274          * @param mixed $res
 275          * @return int
 276          */
 277         public function numFields( $res ) {
 278                 if ( $res instanceof ResultWrapper ) {
 279                         $res = $res->result;
 280                 }
 281
 282                 return sqlsrv_num_fields( $res );
 283         }
 284
 285         /**
 286          * @param mixed $res
 287          * @param int $n
 288          * @return int
 289          */
 290         public function fieldName( $res, $n ) {
 291                 if ( $res instanceof ResultWrapper ) {
 292                         $res = $res->result;
 293                 }
 294
 295                 return sqlsrv_field_metadata( $res )[$n]['Name'];
 296         }
 297
 298         /**
 299          * This must be called after nextSequenceVal
 300          * @return int|null
 301          */
 302         public function insertId() {
 303                 return $this->lastInsertId;
 304         }
 305
 306         /**
 307          * @param MssqlResultWrapper $res
 308          * @param int $row
 309          * @return bool
 310          */
 311         public function dataSeek( $res, $row ) {
 312                 return $res->seek( $row );
 313         }
 314
 315         /**
 316          * @return string
 317          */
 318         public function lastError() {
 319                 $strRet = '';
 320                 $retErrors = sqlsrv_errors( SQLSRV_ERR_ALL );
 321                 if ( $retErrors != null ) {
 322                         foreach ( $retErrors as $arrError ) {
 323                                 $strRet .= $this->formatError( $arrError ) . "\n";
 324                         }
 325                 } else {
 326                         $strRet = "No errors found";
 327                 }
 328
 329                 return $strRet;
 330         }
 331
 332         /**
 333          * @param array $err
 334          * @return string
 335          */
 336         private function formatError( $err ) {
 337                 return '[SQLSTATE ' .
 338                         $err['SQLSTATE'] . '][Error Code ' . $err['code'] . ']' . $err['message'];
 339         }
 340
 341         /**
 342          * @return string|int
 343          */
 344         public function lastErrno() {
 345                 $err = sqlsrv_errors( SQLSRV_ERR_ALL );
 346                 if ( $err !== null && isset( $err[0] ) ) {
 347                         return $err[0]['code'];
 348                 } else {
 349                         return 0;
 350                 }
 351         }
 352
 353         protected function wasKnownStatementRollbackError() {
 354                 $errors = sqlsrv_errors( SQLSRV_ERR_ALL );
 355                 if ( !$errors ) {
 356                         return false;
 357                 }
 358                 // The transaction vs statement rollback behavior depends on XACT_ABORT, so make sure
 359                 // that the "statement has been terminated" error (3621) is specifically present.
 360                 // https://docs.microsoft.com/en-us/sql/t-sql/statements/set-xact-abort-transact-sql
 361                 $statementOnly = false;
 362                 $codeWhitelist = [ '2601', '2627', '547' ];
 363                 foreach ( $errors as $error ) {
 364                         if ( $error['code'] == '3621' ) {
 365                                 $statementOnly = true;
 366                         } elseif ( !in_array( $error['code'], $codeWhitelist ) ) {
 367                                 $statementOnly = false;
 368                                 break;
 369                         }
 370                 }
 371
 372                 return $statementOnly;
 373         }
 374
 375         /**
 376          * @return int
 377          */
 378         protected function fetchAffectedRowCount() {
 379                 return $this->lastAffectedRowCount;
 380         }
 381
 382         /**
 383          * SELECT wrapper
 384          *
 385          * @param mixed $table Array or string, table name(s) (prefix auto-added)
 386          * @param mixed $vars Array or string, field name(s) to be retrieved
 387          * @param mixed $conds Array or string, condition(s) for WHERE
 388          * @param string $fname Calling function name (use __METHOD__) for logs/profiling
 389          * @param array $options Associative array of options (e.g.
 390          *   [ 'GROUP BY' => 'page_title' ]), see Database::makeSelectOptions
 391          *   code for list of supported stuff
 392          * @param array $join_conds Associative array of table join conditions
 393          *   (optional) (e.g. [ 'page' => [ 'LEFT JOIN','page_latest=rev_id' ] ]
 394          * @return mixed Database result resource (feed to Database::fetchObject
 395          *   or whatever), or false on failure
 396          * @throws DBQueryError
 397          * @throws DBUnexpectedError
 398          * @throws Exception
 399          */
 400         public function select( $table, $vars, $conds = '', $fname = __METHOD__,
 401                 $options = [], $join_conds = []
 402         ) {
 403                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 404                 if ( isset( $options['EXPLAIN'] ) ) {
 405                         try {
 406                                 $this->scrollableCursor = false;
 407                                 $this->prepareStatements = false;
 408                                 $this->query( "SET SHOWPLAN_ALL ON" );
 409                                 $ret = $this->query( $sql, $fname );
 410                                 $this->query( "SET SHOWPLAN_ALL OFF" );
 411                         } catch ( DBQueryError $dqe ) {
 412                                 if ( isset( $options['FOR COUNT'] ) ) {
 413                                         // likely don't have privs for SHOWPLAN, so run a select count instead
 414                                         $this->query( "SET SHOWPLAN_ALL OFF" );
 415                                         unset( $options['EXPLAIN'] );
 416                                         $ret = $this->select(
 417                                                 $table,
 418                                                 'COUNT(*) AS EstimateRows',
 419                                                 $conds,
 420                                                 $fname,
 421                                                 $options,
 422                                                 $join_conds
 423                                         );
 424                                 } else {
 425                                         // someone actually wanted the query plan instead of an est row count
 426                                         // let them know of the error
 427                                         $this->scrollableCursor = true;
 428                                         $this->prepareStatements = true;
 429                                         throw $dqe;
 430                                 }
 431                         }
 432                         $this->scrollableCursor = true;
 433                         $this->prepareStatements = true;
 434                         return $ret;
 435                 }
 436                 return $this->query( $sql, $fname );
 437         }
 438
 439         /**
 440          * SELECT wrapper
 441          *
 442          * @param mixed $table Array or string, table name(s) (prefix auto-added)
 443          * @param mixed $vars Array or string, field name(s) to be retrieved
 444          * @param mixed $conds Array or string, condition(s) for WHERE
 445          * @param string $fname Calling function name (use __METHOD__) for logs/profiling
 446          * @param array $options Associative array of options (e.g. [ 'GROUP BY' => 'page_title' ]),
 447          *   see Database::makeSelectOptions code for list of supported stuff
 448          * @param array $join_conds Associative array of table join conditions (optional)
 449          *    (e.g. [ 'page' => [ 'LEFT JOIN','page_latest=rev_id' ] ]
 450          * @return string The SQL text
 451          */
 452         public function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 453                 $options = [], $join_conds = []
 454         ) {
 455                 if ( isset( $options['EXPLAIN'] ) ) {
 456                         unset( $options['EXPLAIN'] );
 457                 }
 458
 459                 $sql = parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 460
 461                 // try to rewrite aggregations of bit columns (currently MAX and MIN)
 462                 if ( strpos( $sql, 'MAX(' ) !== false || strpos( $sql, 'MIN(' ) !== false ) {
 463                         $bitColumns = [];
 464                         if ( is_array( $table ) ) {
 465                                 $tables = $table;
 466                                 while ( $tables ) {
 467                                         $t = array_pop( $tables );
 468                                         if ( is_array( $t ) ) {
 469                                                 $tables = array_merge( $tables, $t );
 470                                         } else {
 471                                                 $bitColumns += $this->getBitColumns( $this->tableName( $t ) );
 472                                         }
 473                                 }
 474                         } else {
 475                                 $bitColumns = $this->getBitColumns( $this->tableName( $table ) );
 476                         }
 477
 478                         foreach ( $bitColumns as $col => $info ) {
 479                                 $replace = [
 480                                         "MAX({$col})" => "MAX(CAST({$col} AS tinyint))",
 481                                         "MIN({$col})" => "MIN(CAST({$col} AS tinyint))",
 482                                 ];
 483                                 $sql = str_replace( array_keys( $replace ), array_values( $replace ), $sql );
 484                         }
 485                 }
 486
 487                 return $sql;
 488         }
 489
 490         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
 491                 $fname = __METHOD__
 492         ) {
 493                 $this->scrollableCursor = false;
 494                 try {
 495                         parent::deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname );
 496                 } catch ( Exception $e ) {
 497                         $this->scrollableCursor = true;
 498                         throw $e;
 499                 }
 500                 $this->scrollableCursor = true;
 501         }
 502
 503         public function delete( $table, $conds, $fname = __METHOD__ ) {
 504                 $this->scrollableCursor = false;
 505                 try {
 506                         parent::delete( $table, $conds, $fname );
 507                 } catch ( Exception $e ) {
 508                         $this->scrollableCursor = true;
 509                         throw $e;
 510                 }
 511                 $this->scrollableCursor = true;
 512         }
 513
 514         /**
 515          * Estimate rows in dataset
 516          * Returns estimated count, based on SHOWPLAN_ALL output
 517          * This is not necessarily an accurate estimate, so use sparingly
 518          * Returns -1 if count cannot be found
 519          * Takes same arguments as Database::select()
 520          * @param string $table
 521          * @param string $var
 522          * @param string $conds
 523          * @param string $fname
 524          * @param array $options
 525          * @param array $join_conds
 526          * @return int
 527          */
 528         public function estimateRowCount( $table, $var = '*', $conds = '',
 529                 $fname = __METHOD__, $options = [], $join_conds = []
 530         ) {
 531                 $conds = $this->normalizeConditions( $conds, $fname );
 532                 $column = $this->extractSingleFieldFromList( $var );
 533                 if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
 534                         $conds[] = "$column IS NOT NULL";
 535                 }
 536
 537                 // http://msdn2.microsoft.com/en-us/library/aa259203.aspx
 538                 $options['EXPLAIN'] = true;
 539                 $options['FOR COUNT'] = true;
 540                 $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
 541
 542                 $rows = -1;
 543                 if ( $res ) {
 544                         $row = $this->fetchRow( $res );
 545
 546                         if ( isset( $row['EstimateRows'] ) ) {
 547                                 $rows = (int)$row['EstimateRows'];
 548                         }
 549                 }
 550
 551                 return $rows;
 552         }
 553
 554         /**
 555          * Returns information about an index
 556          * If errors are explicitly ignored, returns NULL on failure
 557          * @param string $table
 558          * @param string $index
 559          * @param string $fname
 560          * @return array|bool|null
 561          */
 562         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 563                 # This does not return the same info as MYSQL would, but that's OK
 564                 # because MediaWiki never uses the returned value except to check for
 565                 # the existence of indexes.
 566                 $sql = "sp_helpindex '" . $this->tableName( $table ) . "'";
 567                 $res = $this->query( $sql, $fname );
 568
 569                 if ( !$res ) {
 570                         return null;
 571                 }
 572
 573                 $result = [];
 574                 foreach ( $res as $row ) {
 575                         if ( $row->index_name == $index ) {
 576                                 $row->Non_unique = !stristr( $row->index_description, "unique" );
 577                                 $cols = explode( ", ", $row->index_keys );
 578                                 foreach ( $cols as $col ) {
 579                                         $row->Column_name = trim( $col );
 580                                         $result[] = clone $row;
 581                                 }
 582                         } elseif ( $index == 'PRIMARY' && stristr( $row->index_description, 'PRIMARY' ) ) {
 583                                 $row->Non_unique = 0;
 584                                 $cols = explode( ", ", $row->index_keys );
 585                                 foreach ( $cols as $col ) {
 586                                         $row->Column_name = trim( $col );
 587                                         $result[] = clone $row;
 588                                 }
 589                         }
 590                 }
 591
 592                 return $result ?: false;
 593         }
 594
 595         /**
 596          * INSERT wrapper, inserts an array into a table
 597          *
 598          * $arrToInsert may be a single associative array, or an array of these with numeric keys, for
 599          * multi-row insert.
 600          *
 601          * Usually aborts on failure
 602          * If errors are explicitly ignored, returns success
 603          * @param string $table
 604          * @param array $arrToInsert
 605          * @param string $fname
 606          * @param array $options
 607          * @return bool
 608          * @throws Exception
 609          */
 610         public function insert( $table, $arrToInsert, $fname = __METHOD__, $options = [] ) {
 611                 # No rows to insert, easy just return now
 612                 if ( !count( $arrToInsert ) ) {
 613                         return true;
 614                 }
 615
 616                 if ( !is_array( $options ) ) {
 617                         $options = [ $options ];
 618                 }
 619
 620                 $table = $this->tableName( $table );
 621
 622                 if ( !( isset( $arrToInsert[0] ) && is_array( $arrToInsert[0] ) ) ) { // Not multi row
 623                         $arrToInsert = [ 0 => $arrToInsert ]; // make everything multi row compatible
 624                 }
 625
 626                 // We know the table we're inserting into, get its identity column
 627                 $identity = null;
 628                 // strip matching square brackets and the db/schema from table name
 629                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
 630                 $tableRaw = array_pop( $tableRawArr );
 631                 $res = $this->doQuery(
 632                         "SELECT NAME AS idColumn FROM SYS.IDENTITY_COLUMNS " .
 633                                 "WHERE OBJECT_NAME(OBJECT_ID)='{$tableRaw}'"
 634                 );
 635                 if ( $res && sqlsrv_has_rows( $res ) ) {
 636                         // There is an identity for this table.
 637                         $identityArr = sqlsrv_fetch_array( $res, SQLSRV_FETCH_ASSOC );
 638                         $identity = array_pop( $identityArr );
 639                 }
 640                 sqlsrv_free_stmt( $res );
 641
 642                 // Determine binary/varbinary fields so we can encode data as a hex string like 0xABCDEF
 643                 $binaryColumns = $this->getBinaryColumns( $table );
 644
 645                 // INSERT IGNORE is not supported by SQL Server
 646                 // remove IGNORE from options list and set ignore flag to true
 647                 if ( in_array( 'IGNORE', $options ) ) {
 648                         $options = array_diff( $options, [ 'IGNORE' ] );
 649                         $this->ignoreDupKeyErrors = true;
 650                 }
 651
 652                 $ret = null;
 653                 foreach ( $arrToInsert as $a ) {
 654                         // start out with empty identity column, this is so we can return
 655                         // it as a result of the INSERT logic
 656                         $sqlPre = '';
 657                         $sqlPost = '';
 658                         $identityClause = '';
 659
 660                         // if we have an identity column
 661                         if ( $identity ) {
 662                                 // iterate through
 663                                 foreach ( $a as $k => $v ) {
 664                                         if ( $k == $identity ) {
 665                                                 if ( !is_null( $v ) ) {
 666                                                         // there is a value being passed to us,
 667                                                         // we need to turn on and off inserted identity
 668                                                         $sqlPre = "SET IDENTITY_INSERT $table ON;";
 669                                                         $sqlPost = ";SET IDENTITY_INSERT $table OFF;";
 670                                                 } else {
 671                                                         // we can't insert NULL into an identity column,
 672                                                         // so remove the column from the insert.
 673                                                         unset( $a[$k] );
 674                                                 }
 675                                         }
 676                                 }
 677
 678                                 // we want to output an identity column as result
 679                                 $identityClause = "OUTPUT INSERTED.$identity ";
 680                         }
 681
 682                         $keys = array_keys( $a );
 683
 684                         // Build the actual query
 685                         $sql = $sqlPre . 'INSERT ' . implode( ' ', $options ) .
 686                                 " INTO $table (" . implode( ',', $keys ) . ") $identityClause VALUES (";
 687
 688                         $first = true;
 689                         foreach ( $a as $key => $value ) {
 690                                 if ( isset( $binaryColumns[$key] ) ) {
 691                                         $value = new MssqlBlob( $value );
 692                                 }
 693                                 if ( $first ) {
 694                                         $first = false;
 695                                 } else {
 696                                         $sql .= ',';
 697                                 }
 698                                 if ( is_null( $value ) ) {
 699                                         $sql .= 'null';
 700                                 } elseif ( is_array( $value ) || is_object( $value ) ) {
 701                                         if ( is_object( $value ) && $value instanceof Blob ) {
 702                                                 $sql .= $this->addQuotes( $value );
 703                                         } else {
 704                                                 $sql .= $this->addQuotes( serialize( $value ) );
 705                                         }
 706                                 } else {
 707                                         $sql .= $this->addQuotes( $value );
 708                                 }
 709                         }
 710                         $sql .= ')' . $sqlPost;
 711
 712                         // Run the query
 713                         $this->scrollableCursor = false;
 714                         try {
 715                                 $ret = $this->query( $sql );
 716                         } catch ( Exception $e ) {
 717                                 $this->scrollableCursor = true;
 718                                 $this->ignoreDupKeyErrors = false;
 719                                 throw $e;
 720                         }
 721                         $this->scrollableCursor = true;
 722
 723                         if ( $ret instanceof ResultWrapper && !is_null( $identity ) ) {
 724                                 // Then we want to get the identity column value we were assigned and save it off
 725                                 $row = $ret->fetchObject();
 726                                 if ( is_object( $row ) ) {
 727                                         $this->lastInsertId = $row->$identity;
 728                                         // It seems that mAffectedRows is -1 sometimes when OUTPUT INSERTED.identity is
 729                                         // used if we got an identity back, we know for sure a row was affected, so
 730                                         // adjust that here
 731                                         if ( $this->lastAffectedRowCount == -1 ) {
 732                                                 $this->lastAffectedRowCount = 1;
 733                                         }
 734                                 }
 735                         }
 736                 }
 737
 738                 $this->ignoreDupKeyErrors = false;
 739
 740                 return $ret;
 741         }
 742
 743         /**
 744          * INSERT SELECT wrapper
 745          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 746          * Source items may be literals rather than field names, but strings should
 747          * be quoted with Database::addQuotes().
 748          * @param string $destTable
 749          * @param array|string $srcTable May be an array of tables.
 750          * @param array $varMap
 751          * @param array $conds May be "*" to copy the whole table.
 752          * @param string $fname
 753          * @param array $insertOptions
 754          * @param array $selectOptions
 755          * @param array $selectJoinConds
 756          * @return bool
 757          * @throws Exception
 758          */
 759         public function nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 760                 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
 761         ) {
 762                 $this->scrollableCursor = false;
 763                 try {
 764                         $ret = parent::nativeInsertSelect(
 765                                 $destTable,
 766                                 $srcTable,
 767                                 $varMap,
 768                                 $conds,
 769                                 $fname,
 770                                 $insertOptions,
 771                                 $selectOptions,
 772                                 $selectJoinConds
 773                         );
 774                 } catch ( Exception $e ) {
 775                         $this->scrollableCursor = true;
 776                         throw $e;
 777                 }
 778                 $this->scrollableCursor = true;
 779
 780                 return $ret;
 781         }
 782
 783         /**
 784          * UPDATE wrapper. Takes a condition array and a SET array.
 785          *
 786          * @param string $table Name of the table to UPDATE. This will be passed through
 787          *                Database::tableName().
 788          *
 789          * @param array $values An array of values to SET. For each array element,
 790          *                the key gives the field name, and the value gives the data
 791          *                to set that field to. The data will be quoted by
 792          *                Database::addQuotes().
 793          *
 794          * @param array $conds An array of conditions (WHERE). See
 795          *                Database::select() for the details of the format of
 796          *                condition arrays. Use '*' to update all rows.
 797          *
 798          * @param string $fname The function name of the caller (from __METHOD__),
 799          *                for logging and profiling.
 800          *
 801          * @param array $options An array of UPDATE options, can be:
 802          *                   - IGNORE: Ignore unique key conflicts
 803          *                   - LOW_PRIORITY: MySQL-specific, see MySQL manual.
 804          * @return bool
 805          * @throws DBUnexpectedError
 806          * @throws Exception
 807          */
 808         function update( $table, $values, $conds, $fname = __METHOD__, $options = [] ) {
 809                 $table = $this->tableName( $table );
 810                 $binaryColumns = $this->getBinaryColumns( $table );
 811
 812                 $opts = $this->makeUpdateOptions( $options );
 813                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET, $binaryColumns );
 814
 815                 if ( $conds !== [] && $conds !== '*' ) {
 816                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND, $binaryColumns );
 817                 }
 818
 819                 $this->scrollableCursor = false;
 820                 try {
 821                         $this->query( $sql );
 822                 } catch ( Exception $e ) {
 823                         $this->scrollableCursor = true;
 824                         throw $e;
 825                 }
 826                 $this->scrollableCursor = true;
 827                 return true;
 828         }
 829
 830         /**
 831          * Makes an encoded list of strings from an array
 832          * @param array $a Containing the data
 833          * @param int $mode Constant
 834          *      - LIST_COMMA:          comma separated, no field names
 835          *      - LIST_AND:            ANDed WHERE clause (without the WHERE). See
 836          *        the documentation for $conds in Database::select().
 837          *      - LIST_OR:             ORed WHERE clause (without the WHERE)
 838          *      - LIST_SET:            comma separated with field names, like a SET clause
 839          *      - LIST_NAMES:          comma separated field names
 840          * @param array $binaryColumns Contains a list of column names that are binary types
 841          *      This is a custom parameter only present for MS SQL.
 842          *
 843          * @throws DBUnexpectedError
 844          * @return string
 845          */
 846         public function makeList( $a, $mode = LIST_COMMA, $binaryColumns = [] ) {
 847                 if ( !is_array( $a ) ) {
 848                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with incorrect parameters' );
 849                 }
 850
 851                 if ( $mode != LIST_NAMES ) {
 852                         // In MS SQL, values need to be specially encoded when they are
 853                         // inserted into binary fields. Perform this necessary encoding
 854                         // for the specified set of columns.
 855                         foreach ( array_keys( $a ) as $field ) {
 856                                 if ( !isset( $binaryColumns[$field] ) ) {
 857                                         continue;
 858                                 }
 859
 860                                 if ( is_array( $a[$field] ) ) {
 861                                         foreach ( $a[$field] as &$v ) {
 862                                                 $v = new MssqlBlob( $v );
 863                                         }
 864                                         unset( $v );
 865                                 } else {
 866                                         $a[$field] = new MssqlBlob( $a[$field] );
 867                                 }
 868                         }
 869                 }
 870
 871                 return parent::makeList( $a, $mode );
 872         }
 873
 874         /**
 875          * @param string $table
 876          * @param string $field
 877          * @return int Returns the size of a text field, or -1 for "unlimited"
 878          */
 879         public function textFieldSize( $table, $field ) {
 880                 $table = $this->tableName( $table );
 881                 $sql = "SELECT CHARACTER_MAXIMUM_LENGTH,DATA_TYPE FROM INFORMATION_SCHEMA.Columns
 882                         WHERE TABLE_NAME = '$table' AND COLUMN_NAME = '$field'";
 883                 $res = $this->query( $sql );
 884                 $row = $this->fetchRow( $res );
 885                 $size = -1;
 886                 if ( strtolower( $row['DATA_TYPE'] ) != 'text' ) {
 887                         $size = $row['CHARACTER_MAXIMUM_LENGTH'];
 888                 }
 889
 890                 return $size;
 891         }
 892
 893         /**
 894          * Construct a LIMIT query with optional offset
 895          * This is used for query pages
 896          *
 897          * @param string $sql SQL query we will append the limit too
 898          * @param int $limit The SQL limit
 899          * @param bool|int $offset The SQL offset (default false)
 900          * @return array|string
 901          * @throws DBUnexpectedError
 902          */
 903         public function limitResult( $sql, $limit, $offset = false ) {
 904                 if ( $offset === false || $offset == 0 ) {
 905                         if ( strpos( $sql, "SELECT" ) === false ) {
 906                                 return "TOP {$limit} " . $sql;
 907                         } else {
 908                                 return preg_replace( '/\bSELECT(\s+DISTINCT)?\b/Dsi',
 909                                         'SELECT$1 TOP ' . $limit, $sql, 1 );
 910                         }
 911                 } else {
 912                         // This one is fun, we need to pull out the select list as well as any ORDER BY clause
 913                         $select = $orderby = [];
 914                         $s1 = preg_match( '#SELECT\s+(.+?)\s+FROM#Dis', $sql, $select );
 915                         $s2 = preg_match( '#(ORDER BY\s+.+?)(\s*FOR XML .*)?$#Dis', $sql, $orderby );
 916                         $postOrder = '';
 917                         $first = $offset + 1;
 918                         $last = $offset + $limit;
 919                         $sub1 = 'sub_' . $this->subqueryId;
 920                         $sub2 = 'sub_' . ( $this->subqueryId + 1 );
 921                         $this->subqueryId += 2;
 922                         if ( !$s1 ) {
 923                                 // wat
 924                                 throw new DBUnexpectedError( $this, "Attempting to LIMIT a non-SELECT query\n" );
 925                         }
 926                         if ( !$s2 ) {
 927                                 // no ORDER BY
 928                                 $overOrder = 'ORDER BY (SELECT 1)';
 929                         } else {
 930                                 if ( !isset( $orderby[2] ) || !$orderby[2] ) {
 931                                         // don't need to strip it out if we're using a FOR XML clause
 932                                         $sql = str_replace( $orderby[1], '', $sql );
 933                                 }
 934                                 $overOrder = $orderby[1];
 935                                 $postOrder = ' ' . $overOrder;
 936                         }
 937                         $sql = "SELECT {$select[1]}
 938                                         FROM (
 939                                                 SELECT ROW_NUMBER() OVER({$overOrder}) AS rowNumber, *
 940                                                 FROM ({$sql}) {$sub1}
 941                                         ) {$sub2}
 942                                         WHERE rowNumber BETWEEN {$first} AND {$last}{$postOrder}";
 943
 944                         return $sql;
 945                 }
 946         }
 947
 948         /**
 949          * If there is a limit clause, parse it, strip it, and pass the remaining
 950          * SQL through limitResult() with the appropriate parameters. Not the
 951          * prettiest solution, but better than building a whole new parser. This
 952          * exists becase there are still too many extensions that don't use dynamic
 953          * sql generation.
 954          *
 955          * @param string $sql
 956          * @return array|mixed|string
 957          */
 958         public function LimitToTopN( $sql ) {
 959                 // Matches: LIMIT {[offset,] row_count | row_count OFFSET offset}
 960                 $pattern = '/\bLIMIT\s+((([0-9]+)\s*,\s*)?([0-9]+)(\s+OFFSET\s+([0-9]+))?)/i';
 961                 if ( preg_match( $pattern, $sql, $matches ) ) {
 962                         $row_count = $matches[4];
 963                         $offset = $matches[3] ?: $matches[6] ?: false;
 964
 965                         // strip the matching LIMIT clause out
 966                         $sql = str_replace( $matches[0], '', $sql );
 967
 968                         return $this->limitResult( $sql, $row_count, $offset );
 969                 }
 970
 971                 return $sql;
 972         }
 973
 974         /**
 975          * @return string Wikitext of a link to the server software's web site
 976          */
 977         public function getSoftwareLink() {
 978                 return "[{{int:version-db-mssql-url}} MS SQL Server]";
 979         }
 980
 981         /**
 982          * @return string Version information from the database
 983          */
 984         public function getServerVersion() {
 985                 $server_info = sqlsrv_server_info( $this->conn );
 986                 $version = 'Error';
 987                 if ( isset( $server_info['SQLServerVersion'] ) ) {
 988                         $version = $server_info['SQLServerVersion'];
 989                 }
 990
 991                 return $version;
 992         }
 993
 994         /**
 995          * @param string $table
 996          * @param string $fname
 997          * @return bool
 998          */
 999         public function tableExists( $table, $fname = __METHOD__ ) {
1000                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
1001
1002                 if ( $db !== false ) {
1003                         // remote database
1004                         $this->queryLogger->error( "Attempting to call tableExists on a remote table" );
1005                         return false;
1006                 }
1007
1008                 if ( $schema === false ) {
1009                         $schema = $this->schema;
1010                 }
1011
1012                 $res = $this->query( "SELECT 1 FROM INFORMATION_SCHEMA.TABLES
1013                         WHERE TABLE_TYPE = 'BASE TABLE'
1014                         AND TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table'" );
1015
1016                 if ( $res->numRows() ) {
1017                         return true;
1018                 } else {
1019                         return false;
1020                 }
1021         }
1022
1023         /**
1024          * Query whether a given column exists in the mediawiki schema
1025          * @param string $table
1026          * @param string $field
1027          * @param string $fname
1028          * @return bool
1029          */
1030         public function fieldExists( $table, $field, $fname = __METHOD__ ) {
1031                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
1032
1033                 if ( $db !== false ) {
1034                         // remote database
1035                         $this->queryLogger->error( "Attempting to call fieldExists on a remote table" );
1036                         return false;
1037                 }
1038
1039                 $res = $this->query( "SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS
1040                         WHERE TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table' AND COLUMN_NAME = '$field'" );
1041
1042                 if ( $res->numRows() ) {
1043                         return true;
1044                 } else {
1045                         return false;
1046                 }
1047         }
1048
1049         public function fieldInfo( $table, $field ) {
1050                 list( $db, $schema, $table ) = $this->tableName( $table, 'split' );
1051
1052                 if ( $db !== false ) {
1053                         // remote database
1054                         $this->queryLogger->error( "Attempting to call fieldInfo on a remote table" );
1055                         return false;
1056                 }
1057
1058                 $res = $this->query( "SELECT * FROM INFORMATION_SCHEMA.COLUMNS
1059                         WHERE TABLE_SCHEMA = '$schema' AND TABLE_NAME = '$table' AND COLUMN_NAME = '$field'" );
1060
1061                 $meta = $res->fetchRow();
1062                 if ( $meta ) {
1063                         return new MssqlField( $meta );
1064                 }
1065
1066                 return false;
1067         }
1068
1069         protected function doSavepoint( $identifier, $fname ) {
1070                 $this->query( 'SAVE TRANSACTION ' . $this->addIdentifierQuotes( $identifier ), $fname );
1071         }
1072
1073         protected function doReleaseSavepoint( $identifier, $fname ) {
1074                 // Not supported. Also not really needed, a new doSavepoint() for the
1075                 // same identifier will overwrite the old.
1076         }
1077
1078         protected function doRollbackToSavepoint( $identifier, $fname ) {
1079                 $this->query( 'ROLLBACK TRANSACTION ' . $this->addIdentifierQuotes( $identifier ), $fname );
1080         }
1081
1082         /**
1083          * Begin a transaction, committing any previously open transaction
1084          * @param string $fname
1085          */
1086         protected function doBegin( $fname = __METHOD__ ) {
1087                 sqlsrv_begin_transaction( $this->conn );
1088                 $this->trxLevel = 1;
1089         }
1090
1091         /**
1092          * End a transaction
1093          * @param string $fname
1094          */
1095         protected function doCommit( $fname = __METHOD__ ) {
1096                 sqlsrv_commit( $this->conn );
1097                 $this->trxLevel = 0;
1098         }
1099
1100         /**
1101          * Rollback a transaction.
1102          * No-op on non-transactional databases.
1103          * @param string $fname
1104          */
1105         protected function doRollback( $fname = __METHOD__ ) {
1106                 sqlsrv_rollback( $this->conn );
1107                 $this->trxLevel = 0;
1108         }
1109
1110         /**
1111          * @param string $s
1112          * @return string
1113          */
1114         public function strencode( $s ) {
1115                 // Should not be called by us
1116                 return str_replace( "'", "''", $s );
1117         }
1118
1119         /**
1120          * @param string|int|null|bool|Blob $s
1121          * @return string|int
1122          */
1123         public function addQuotes( $s ) {
1124                 if ( $s instanceof MssqlBlob ) {
1125                         return $s->fetch();
1126                 } elseif ( $s instanceof Blob ) {
1127                         // this shouldn't really ever be called, but it's here if needed
1128                         // (and will quite possibly make the SQL error out)
1129                         $blob = new MssqlBlob( $s->fetch() );
1130                         return $blob->fetch();
1131                 } else {
1132                         if ( is_bool( $s ) ) {
1133                                 $s = $s ? 1 : 0;
1134                         }
1135                         return parent::addQuotes( $s );
1136                 }
1137         }
1138
1139         /**
1140          * @param string $s
1141          * @return string
1142          */
1143         public function addIdentifierQuotes( $s ) {
1144                 // http://msdn.microsoft.com/en-us/library/aa223962.aspx
1145                 return '[' . $s . ']';
1146         }
1147
1148         /**
1149          * @param string $name
1150          * @return bool
1151          */
1152         public function isQuotedIdentifier( $name ) {
1153                 return strlen( $name ) && $name[0] == '[' && substr( $name, -1, 1 ) == ']';
1154         }
1155
1156         /**
1157          * MS SQL supports more pattern operators than other databases (ex: [,],^)
1158          *
1159          * @param string $s
1160          * @param string $escapeChar
1161          * @return string
1162          */
1163         protected function escapeLikeInternal( $s, $escapeChar = '`' ) {
1164                 return str_replace( [ $escapeChar, '%', '_', '[', ']', '^' ],
1165                         [ "{$escapeChar}{$escapeChar}", "{$escapeChar}%", "{$escapeChar}_",
1166                                 "{$escapeChar}[", "{$escapeChar}]", "{$escapeChar}^" ],
1167                         $s );
1168         }
1169
1170         /**
1171          * @param string $db
1172          * @return bool
1173          */
1174         public function selectDB( $db ) {
1175                 try {
1176                         $this->dbName = $db;
1177                         $this->query( "USE $db" );
1178                         return true;
1179                 } catch ( Exception $e ) {
1180                         return false;
1181                 }
1182         }
1183
1184         /**
1185          * @param array $options An associative array of options to be turned into
1186          *   an SQL query, valid keys are listed in the function.
1187          * @return array
1188          */
1189         public function makeSelectOptions( $options ) {
1190                 $tailOpts = '';
1191                 $startOpts = '';
1192
1193                 $noKeyOptions = [];
1194                 foreach ( $options as $key => $option ) {
1195                         if ( is_numeric( $key ) ) {
1196                                 $noKeyOptions[$option] = true;
1197                         }
1198                 }
1199
1200                 $tailOpts .= $this->makeGroupByWithHaving( $options );
1201
1202                 $tailOpts .= $this->makeOrderBy( $options );
1203
1204                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1205                         $startOpts .= 'DISTINCT';
1206                 }
1207
1208                 if ( isset( $noKeyOptions['FOR XML'] ) ) {
1209                         // used in group concat field emulation
1210                         $tailOpts .= " FOR XML PATH('')";
1211                 }
1212
1213                 // we want this to be compatible with the output of parent::makeSelectOptions()
1214                 return [ $startOpts, '', $tailOpts, '', '' ];
1215         }
1216
1217         public function getType() {
1218                 return 'mssql';
1219         }
1220
1221         /**
1222          * @param array $stringList
1223          * @return string
1224          */
1225         public function buildConcat( $stringList ) {
1226                 return implode( ' + ', $stringList );
1227         }
1228
1229         /**
1230          * Build a GROUP_CONCAT or equivalent statement for a query.
1231          * MS SQL doesn't have GROUP_CONCAT so we emulate it with other stuff (and boy is it nasty)
1232          *
1233          * This is useful for combining a field for several rows into a single string.
1234          * NULL values will not appear in the output, duplicated values will appear,
1235          * and the resulting delimiter-separated values have no defined sort order.
1236          * Code using the results may need to use the PHP unique() or sort() methods.
1237          *
1238          * @param string $delim Glue to bind the results together
1239          * @param string|array $table Table name
1240          * @param string $field Field name
1241          * @param string|array $conds Conditions
1242          * @param string|array $join_conds Join conditions
1243          * @return string SQL text
1244          * @since 1.23
1245          */
1246         public function buildGroupConcatField( $delim, $table, $field, $conds = '',
1247                 $join_conds = []
1248         ) {
1249                 $gcsq = 'gcsq_' . $this->subqueryId;
1250                 $this->subqueryId++;
1251
1252                 $delimLen = strlen( $delim );
1253                 $fld = "{$field} + {$this->addQuotes( $delim )}";
1254                 $sql = "(SELECT LEFT({$field}, LEN({$field}) - {$delimLen}) FROM ("
1255                         . $this->selectSQLText( $table, $fld, $conds, null, [ 'FOR XML' ], $join_conds )
1256                         . ") {$gcsq} ({$field}))";
1257
1258                 return $sql;
1259         }
1260
1261         public function buildSubstring( $input, $startPosition, $length = null ) {
1262                 $this->assertBuildSubstringParams( $startPosition, $length );
1263                 if ( $length === null ) {
1264                         /**
1265                          * MSSQL doesn't allow an empty length parameter, so when we don't want to limit the
1266                          * length returned use the default maximum size of text.
1267                          * @see https://docs.microsoft.com/en-us/sql/t-sql/statements/set-textsize-transact-sql
1268                          */
1269                         $length = 2147483647;
1270                 }
1271                 return 'SUBSTRING(' . implode( ',', [ $input, $startPosition, $length ] ) . ')';
1272         }
1273
1274         /**
1275          * Returns an associative array for fields that are of type varbinary, binary, or image
1276          * $table can be either a raw table name or passed through tableName() first
1277          * @param string $table
1278          * @return array
1279          */
1280         private function getBinaryColumns( $table ) {
1281                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
1282                 $tableRaw = array_pop( $tableRawArr );
1283
1284                 if ( $this->binaryColumnCache === null ) {
1285                         $this->populateColumnCaches();
1286                 }
1287
1288                 return $this->binaryColumnCache[$tableRaw] ?? [];
1289         }
1290
1291         /**
1292          * @param string $table
1293          * @return array
1294          */
1295         private function getBitColumns( $table ) {
1296                 $tableRawArr = explode( '.', preg_replace( '#\[([^\]]*)\]#', '$1', $table ) );
1297                 $tableRaw = array_pop( $tableRawArr );
1298
1299                 if ( $this->bitColumnCache === null ) {
1300                         $this->populateColumnCaches();
1301                 }
1302
1303                 return $this->bitColumnCache[$tableRaw] ?? [];
1304         }
1305
1306         private function populateColumnCaches() {
1307                 $res = $this->select( 'INFORMATION_SCHEMA.COLUMNS', '*',
1308                         [
1309                                 'TABLE_CATALOG' => $this->dbName,
1310                                 'TABLE_SCHEMA' => $this->schema,
1311                                 'DATA_TYPE' => [ 'varbinary', 'binary', 'image', 'bit' ]
1312                         ] );
1313
1314                 $this->binaryColumnCache = [];
1315                 $this->bitColumnCache = [];
1316                 foreach ( $res as $row ) {
1317                         if ( $row->DATA_TYPE == 'bit' ) {
1318                                 $this->bitColumnCache[$row->TABLE_NAME][$row->COLUMN_NAME] = $row;
1319                         } else {
1320                                 $this->binaryColumnCache[$row->TABLE_NAME][$row->COLUMN_NAME] = $row;
1321                         }
1322                 }
1323         }
1324
1325         /**
1326          * @param string $name
1327          * @param string $format
1328          * @return string
1329          */
1330         function tableName( $name, $format = 'quoted' ) {
1331                 # Replace reserved words with better ones
1332                 switch ( $name ) {
1333                         case 'user':
1334                                 return $this->realTableName( 'mwuser', $format );
1335                         default:
1336                                 return $this->realTableName( $name, $format );
1337                 }
1338         }
1339
1340         /**
1341          * call this instead of tableName() in the updater when renaming tables
1342          * @param string $name
1343          * @param string $format One of quoted, raw, or split
1344          * @return string
1345          */
1346         function realTableName( $name, $format = 'quoted' ) {
1347                 $table = parent::tableName( $name, $format );
1348                 if ( $format == 'split' ) {
1349                         // Used internally, we want the schema split off from the table name and returned
1350                         // as a list with 3 elements (database, schema, table)
1351                         $table = explode( '.', $table );
1352                         while ( count( $table ) < 3 ) {
1353                                 array_unshift( $table, false );
1354                         }
1355                 }
1356                 return $table;
1357         }
1358
1359         /**
1360          * Delete a table
1361          * @param string $tableName
1362          * @param string $fName
1363          * @return bool|ResultWrapper
1364          * @since 1.18
1365          */
1366         public function dropTable( $tableName, $fName = __METHOD__ ) {
1367                 if ( !$this->tableExists( $tableName, $fName ) ) {
1368                         return false;
1369                 }
1370
1371                 // parent function incorrectly appends CASCADE, which we don't want
1372                 $sql = "DROP TABLE " . $this->tableName( $tableName );
1373
1374                 return $this->query( $sql, $fName );
1375         }
1376
1377         /**
1378          * Called in the installer and updater.
1379          * Probably doesn't need to be called anywhere else in the codebase.
1380          * @param bool|null $value
1381          * @return bool|null
1382          */
1383         public function prepareStatements( $value = null ) {
1384                 $old = $this->prepareStatements;
1385                 if ( $value !== null ) {
1386                         $this->prepareStatements = $value;
1387                 }
1388
1389                 return $old;
1390         }
1391
1392         /**
1393          * Called in the installer and updater.
1394          * Probably doesn't need to be called anywhere else in the codebase.
1395          * @param bool|null $value
1396          * @return bool|null
1397          */
1398         public function scrollableCursor( $value = null ) {
1399                 $old = $this->scrollableCursor;
1400                 if ( $value !== null ) {
1401                         $this->scrollableCursor = $value;
1402                 }
1403
1404                 return $old;
1405         }
1406 }
1407
1408 /**
1409  * @deprecated since 1.29
1410  */
1411 class_alias( DatabaseMssql::class, 'DatabaseMssql' );