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mediawiki
Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like DatabaseMssql often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use DatabaseMssql, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 31 | class DatabaseMssql extends DatabaseBase { |
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| 32 | protected $mInsertId = null; |
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| 33 | protected $mLastResult = null; |
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| 34 | protected $mAffectedRows = null; |
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| 35 | protected $mSubqueryId = 0; |
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| 36 | protected $mScrollableCursor = true; |
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| 37 | protected $mPrepareStatements = true; |
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| 38 | protected $mBinaryColumnCache = null; |
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| 39 | protected $mBitColumnCache = null; |
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| 40 | protected $mIgnoreDupKeyErrors = false; |
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| 41 | protected $mIgnoreErrors = []; |
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| 42 | |||
| 43 | protected $mPort; |
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| 44 | |||
| 45 | public function implicitGroupby() { |
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| 48 | |||
| 49 | public function implicitOrderby() { |
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| 52 | |||
| 53 | public function unionSupportsOrderAndLimit() { |
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| 56 | |||
| 57 | /** |
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| 58 | * Usually aborts on failure |
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| 59 | * @param string $server |
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| 60 | * @param string $user |
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| 61 | * @param string $password |
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| 62 | * @param string $dbName |
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| 63 | * @throws DBConnectionError |
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| 64 | * @return bool|resource|null |
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| 65 | */ |
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| 66 | public function open( $server, $user, $password, $dbName ) { |
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| 115 | |||
| 116 | /** |
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| 117 | * Closes a database connection, if it is open |
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| 118 | * Returns success, true if already closed |
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| 119 | * @return bool |
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| 120 | */ |
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| 121 | protected function closeConnection() { |
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| 124 | |||
| 125 | /** |
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| 126 | * @param bool|MssqlResultWrapper|resource $result |
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| 127 | * @return bool|MssqlResultWrapper |
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| 128 | */ |
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| 129 | protected function resultObject( $result ) { |
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| 141 | |||
| 142 | /** |
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| 143 | * @param string $sql |
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| 144 | * @return bool|MssqlResult |
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| 145 | * @throws DBUnexpectedError |
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| 146 | */ |
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| 147 | protected function doQuery( $sql ) { |
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| 221 | |||
| 222 | public function freeResult( $res ) { |
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| 229 | |||
| 230 | /** |
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| 231 | * @param MssqlResultWrapper $res |
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| 232 | * @return stdClass |
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| 233 | */ |
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| 234 | public function fetchObject( $res ) { |
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| 238 | |||
| 239 | /** |
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| 240 | * @param MssqlResultWrapper $res |
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| 241 | * @return array |
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| 242 | */ |
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| 243 | public function fetchRow( $res ) { |
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| 246 | |||
| 247 | /** |
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| 248 | * @param mixed $res |
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| 249 | * @return int |
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| 250 | */ |
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| 251 | public function numRows( $res ) { |
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| 266 | |||
| 267 | /** |
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| 268 | * @param mixed $res |
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| 269 | * @return int |
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| 270 | */ |
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| 271 | public function numFields( $res ) { |
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| 278 | |||
| 279 | /** |
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| 280 | * @param mixed $res |
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| 281 | * @param int $n |
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| 282 | * @return int |
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| 283 | */ |
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| 284 | public function fieldName( $res, $n ) { |
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| 291 | |||
| 292 | /** |
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| 293 | * This must be called after nextSequenceVal |
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| 294 | * @return int|null |
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| 295 | */ |
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| 296 | public function insertId() { |
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| 299 | |||
| 300 | /** |
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| 301 | * @param MssqlResultWrapper $res |
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| 302 | * @param int $row |
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| 303 | * @return bool |
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| 304 | */ |
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| 305 | public function dataSeek( $res, $row ) { |
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| 308 | |||
| 309 | /** |
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| 310 | * @return string |
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| 311 | */ |
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| 312 | public function lastError() { |
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| 325 | |||
| 326 | /** |
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| 327 | * @param array $err |
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| 328 | * @return string |
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| 329 | */ |
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| 330 | private function formatError( $err ) { |
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| 333 | |||
| 334 | /** |
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| 335 | * @return string |
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| 336 | */ |
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| 337 | public function lastErrno() { |
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| 345 | |||
| 346 | /** |
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| 347 | * @return int |
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| 348 | */ |
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| 349 | public function affectedRows() { |
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| 352 | |||
| 353 | /** |
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| 354 | * SELECT wrapper |
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| 355 | * |
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| 356 | * @param mixed $table Array or string, table name(s) (prefix auto-added) |
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| 357 | * @param mixed $vars Array or string, field name(s) to be retrieved |
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| 358 | * @param mixed $conds Array or string, condition(s) for WHERE |
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| 359 | * @param string $fname Calling function name (use __METHOD__) for logs/profiling |
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| 360 | * @param array $options Associative array of options (e.g. |
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| 361 | * [ 'GROUP BY' => 'page_title' ]), see Database::makeSelectOptions |
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| 362 | * code for list of supported stuff |
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| 363 | * @param array $join_conds Associative array of table join conditions |
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| 364 | * (optional) (e.g. [ 'page' => [ 'LEFT JOIN','page_latest=rev_id' ] ] |
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| 365 | * @return mixed Database result resource (feed to Database::fetchObject |
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| 366 | * or whatever), or false on failure |
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| 367 | * @throws DBQueryError |
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| 368 | * @throws DBUnexpectedError |
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| 369 | * @throws Exception |
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| 370 | */ |
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| 371 | public function select( $table, $vars, $conds = '', $fname = __METHOD__, |
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| 409 | |||
| 410 | /** |
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| 411 | * SELECT wrapper |
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| 412 | * |
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| 413 | * @param mixed $table Array or string, table name(s) (prefix auto-added) |
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| 414 | * @param mixed $vars Array or string, field name(s) to be retrieved |
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| 415 | * @param mixed $conds Array or string, condition(s) for WHERE |
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| 416 | * @param string $fname Calling function name (use __METHOD__) for logs/profiling |
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| 417 | * @param array $options Associative array of options (e.g. [ 'GROUP BY' => 'page_title' ]), |
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| 418 | * see Database::makeSelectOptions code for list of supported stuff |
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| 419 | * @param array $join_conds Associative array of table join conditions (optional) |
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| 420 | * (e.g. [ 'page' => [ 'LEFT JOIN','page_latest=rev_id' ] ] |
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| 421 | * @return string The SQL text |
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| 422 | */ |
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| 423 | public function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__, |
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| 454 | |||
| 455 | View Code Duplication | public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, |
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| 467 | |||
| 468 | View Code Duplication | public function delete( $table, $conds, $fname = __METHOD__ ) { |
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| 478 | |||
| 479 | /** |
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| 480 | * Estimate rows in dataset |
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| 481 | * Returns estimated count, based on SHOWPLAN_ALL output |
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| 482 | * This is not necessarily an accurate estimate, so use sparingly |
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| 483 | * Returns -1 if count cannot be found |
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| 484 | * Takes same arguments as Database::select() |
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| 485 | * @param string $table |
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| 486 | * @param string $vars |
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| 487 | * @param string $conds |
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| 488 | * @param string $fname |
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| 489 | * @param array $options |
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| 490 | * @return int |
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| 491 | */ |
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| 492 | View Code Duplication | public function estimateRowCount( $table, $vars = '*', $conds = '', |
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| 511 | |||
| 512 | /** |
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| 513 | * Returns information about an index |
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| 514 | * If errors are explicitly ignored, returns NULL on failure |
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| 515 | * @param string $table |
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| 516 | * @param string $index |
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| 517 | * @param string $fname |
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| 518 | * @return array|bool|null |
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| 519 | */ |
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| 520 | public function indexInfo( $table, $index, $fname = __METHOD__ ) { |
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| 552 | |||
| 553 | /** |
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| 554 | * INSERT wrapper, inserts an array into a table |
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| 555 | * |
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| 556 | * $arrToInsert may be a single associative array, or an array of these with numeric keys, for |
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| 557 | * multi-row insert. |
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| 558 | * |
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| 559 | * Usually aborts on failure |
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| 560 | * If errors are explicitly ignored, returns success |
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| 561 | * @param string $table |
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| 562 | * @param array $arrToInsert |
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| 563 | * @param string $fname |
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| 564 | * @param array $options |
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| 565 | * @return bool |
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| 566 | * @throws Exception |
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| 567 | */ |
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| 568 | public function insert( $table, $arrToInsert, $fname = __METHOD__, $options = [] ) { |
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| 697 | |||
| 698 | /** |
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| 699 | * INSERT SELECT wrapper |
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| 700 | * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ] |
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| 701 | * Source items may be literals rather than field names, but strings should |
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| 702 | * be quoted with Database::addQuotes(). |
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| 703 | * @param string $destTable |
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| 704 | * @param array|string $srcTable May be an array of tables. |
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| 705 | * @param array $varMap |
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| 706 | * @param array $conds May be "*" to copy the whole table. |
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| 707 | * @param string $fname |
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| 708 | * @param array $insertOptions |
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| 709 | * @param array $selectOptions |
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| 710 | * @return null|ResultWrapper |
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| 711 | * @throws Exception |
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| 712 | */ |
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| 713 | public function nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__, |
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| 735 | |||
| 736 | /** |
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| 737 | * UPDATE wrapper. Takes a condition array and a SET array. |
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| 738 | * |
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| 739 | * @param string $table Name of the table to UPDATE. This will be passed through |
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| 740 | * Database::tableName(). |
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| 741 | * |
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| 742 | * @param array $values An array of values to SET. For each array element, |
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| 743 | * the key gives the field name, and the value gives the data |
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| 744 | * to set that field to. The data will be quoted by |
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| 745 | * Database::addQuotes(). |
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| 746 | * |
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| 747 | * @param array $conds An array of conditions (WHERE). See |
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| 748 | * Database::select() for the details of the format of |
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| 749 | * condition arrays. Use '*' to update all rows. |
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| 750 | * |
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| 751 | * @param string $fname The function name of the caller (from __METHOD__), |
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| 752 | * for logging and profiling. |
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| 753 | * |
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| 754 | * @param array $options An array of UPDATE options, can be: |
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| 755 | * - IGNORE: Ignore unique key conflicts |
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| 756 | * - LOW_PRIORITY: MySQL-specific, see MySQL manual. |
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| 757 | * @return bool |
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| 758 | * @throws DBUnexpectedError |
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| 759 | * @throws Exception |
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| 760 | */ |
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| 761 | function update( $table, $values, $conds, $fname = __METHOD__, $options = [] ) { |
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| 782 | |||
| 783 | /** |
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| 784 | * Makes an encoded list of strings from an array |
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| 785 | * @param array $a Containing the data |
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| 786 | * @param int $mode Constant |
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| 787 | * - LIST_COMMA: comma separated, no field names |
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| 788 | * - LIST_AND: ANDed WHERE clause (without the WHERE). See |
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| 789 | * the documentation for $conds in Database::select(). |
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| 790 | * - LIST_OR: ORed WHERE clause (without the WHERE) |
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| 791 | * - LIST_SET: comma separated with field names, like a SET clause |
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| 792 | * - LIST_NAMES: comma separated field names |
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| 793 | * @param array $binaryColumns Contains a list of column names that are binary types |
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| 794 | * This is a custom parameter only present for MS SQL. |
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| 795 | * |
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| 796 | * @throws DBUnexpectedError |
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| 797 | * @return string |
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| 798 | */ |
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| 799 | public function makeList( $a, $mode = LIST_COMMA, $binaryColumns = [] ) { |
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| 826 | |||
| 827 | /** |
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| 828 | * @param string $table |
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| 829 | * @param string $field |
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| 830 | * @return int Returns the size of a text field, or -1 for "unlimited" |
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| 831 | */ |
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| 832 | public function textFieldSize( $table, $field ) { |
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| 845 | |||
| 846 | /** |
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| 847 | * Construct a LIMIT query with optional offset |
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| 848 | * This is used for query pages |
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| 849 | * |
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| 850 | * @param string $sql SQL query we will append the limit too |
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| 851 | * @param int $limit The SQL limit |
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| 852 | * @param bool|int $offset The SQL offset (default false) |
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| 853 | * @return array|string |
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| 854 | * @throws DBUnexpectedError |
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| 855 | */ |
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| 856 | public function limitResult( $sql, $limit, $offset = false ) { |
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| 900 | |||
| 901 | /** |
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| 902 | * If there is a limit clause, parse it, strip it, and pass the remaining |
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| 903 | * SQL through limitResult() with the appropriate parameters. Not the |
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| 904 | * prettiest solution, but better than building a whole new parser. This |
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| 905 | * exists becase there are still too many extensions that don't use dynamic |
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| 906 | * sql generation. |
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| 907 | * |
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| 908 | * @param string $sql |
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| 909 | * @return array|mixed|string |
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| 910 | */ |
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| 911 | public function LimitToTopN( $sql ) { |
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| 926 | |||
| 927 | /** |
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| 928 | * @return string Wikitext of a link to the server software's web site |
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| 929 | */ |
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| 930 | public function getSoftwareLink() { |
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| 933 | |||
| 934 | /** |
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| 935 | * @return string Version information from the database |
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| 936 | */ |
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| 937 | public function getServerVersion() { |
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| 946 | |||
| 947 | /** |
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| 948 | * @param string $table |
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| 949 | * @param string $fname |
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| 950 | * @return bool |
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| 951 | */ |
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| 952 | public function tableExists( $table, $fname = __METHOD__ ) { |
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| 976 | |||
| 977 | /** |
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| 978 | * Query whether a given column exists in the mediawiki schema |
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| 979 | * @param string $table |
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| 980 | * @param string $field |
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| 981 | * @param string $fname |
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| 982 | * @return bool |
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| 983 | */ |
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| 984 | public function fieldExists( $table, $field, $fname = __METHOD__ ) { |
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| 1002 | |||
| 1003 | public function fieldInfo( $table, $field ) { |
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| 1022 | |||
| 1023 | /** |
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| 1024 | * Begin a transaction, committing any previously open transaction |
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| 1025 | * @param string $fname |
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| 1026 | */ |
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| 1027 | protected function doBegin( $fname = __METHOD__ ) { |
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| 1031 | |||
| 1032 | /** |
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| 1033 | * End a transaction |
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| 1034 | * @param string $fname |
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| 1035 | */ |
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| 1036 | protected function doCommit( $fname = __METHOD__ ) { |
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| 1040 | |||
| 1041 | /** |
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| 1042 | * Rollback a transaction. |
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| 1043 | * No-op on non-transactional databases. |
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| 1044 | * @param string $fname |
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| 1045 | */ |
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| 1046 | protected function doRollback( $fname = __METHOD__ ) { |
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| 1050 | |||
| 1051 | /** |
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| 1052 | * Escapes a identifier for use inm SQL. |
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| 1053 | * Throws an exception if it is invalid. |
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| 1054 | * Reference: http://msdn.microsoft.com/en-us/library/aa224033%28v=SQL.80%29.aspx |
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| 1055 | * @param string $identifier |
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| 1056 | * @throws InvalidArgumentException |
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| 1057 | * @return string |
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| 1058 | */ |
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| 1059 | private function escapeIdentifier( $identifier ) { |
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| 1076 | |||
| 1077 | /** |
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| 1078 | * @param string $s |
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| 1079 | * @return string |
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| 1080 | */ |
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| 1081 | public function strencode( $s ) { |
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| 1086 | |||
| 1087 | /** |
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| 1088 | * @param string|int|null|bool|Blob $s |
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| 1089 | * @return string|int |
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| 1090 | */ |
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| 1091 | public function addQuotes( $s ) { |
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| 1106 | |||
| 1107 | /** |
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| 1108 | * @param string $s |
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| 1109 | * @return string |
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| 1110 | */ |
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| 1111 | public function addIdentifierQuotes( $s ) { |
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| 1115 | |||
| 1116 | /** |
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| 1117 | * @param string $name |
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| 1118 | * @return bool |
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| 1119 | */ |
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| 1120 | public function isQuotedIdentifier( $name ) { |
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| 1123 | |||
| 1124 | /** |
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| 1125 | * MS SQL supports more pattern operators than other databases (ex: [,],^) |
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| 1126 | * |
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| 1127 | * @param string $s |
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| 1128 | * @return string |
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| 1129 | */ |
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| 1130 | protected function escapeLikeInternal( $s ) { |
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| 1133 | |||
| 1134 | /** |
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| 1135 | * MS SQL requires specifying the escape character used in a LIKE query |
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| 1136 | * or using Square brackets to surround characters that are to be escaped |
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| 1137 | * https://msdn.microsoft.com/en-us/library/ms179859.aspx |
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| 1138 | * Here we take the Specify-Escape-Character approach since it's less |
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| 1139 | * invasive, renders a query that is closer to other DB's and better at |
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| 1140 | * handling square bracket escaping |
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| 1141 | * |
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| 1142 | * @return string Fully built LIKE statement |
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| 1143 | */ |
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| 1144 | View Code Duplication | public function buildLike() { |
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| 1152 | |||
| 1153 | /** |
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| 1154 | * @param string $db |
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| 1155 | * @return bool |
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| 1156 | */ |
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| 1157 | public function selectDB( $db ) { |
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| 1166 | |||
| 1167 | /** |
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| 1168 | * @param array $options An associative array of options to be turned into |
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| 1169 | * an SQL query, valid keys are listed in the function. |
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| 1170 | * @return array |
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| 1171 | */ |
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| 1172 | public function makeSelectOptions( $options ) { |
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| 1199 | |||
| 1200 | /** |
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| 1201 | * Get the type of the DBMS, as it appears in $wgDBtype. |
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| 1202 | * @return string |
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| 1203 | */ |
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| 1204 | public function getType() { |
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| 1207 | |||
| 1208 | /** |
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| 1209 | * @param array $stringList |
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| 1210 | * @return string |
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| 1211 | */ |
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| 1212 | public function buildConcat( $stringList ) { |
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| 1215 | |||
| 1216 | /** |
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| 1217 | * Build a GROUP_CONCAT or equivalent statement for a query. |
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| 1218 | * MS SQL doesn't have GROUP_CONCAT so we emulate it with other stuff (and boy is it nasty) |
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| 1219 | * |
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| 1220 | * This is useful for combining a field for several rows into a single string. |
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| 1221 | * NULL values will not appear in the output, duplicated values will appear, |
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| 1222 | * and the resulting delimiter-separated values have no defined sort order. |
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| 1223 | * Code using the results may need to use the PHP unique() or sort() methods. |
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| 1224 | * |
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| 1225 | * @param string $delim Glue to bind the results together |
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| 1226 | * @param string|array $table Table name |
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| 1227 | * @param string $field Field name |
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| 1228 | * @param string|array $conds Conditions |
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| 1229 | * @param string|array $join_conds Join conditions |
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| 1230 | * @return string SQL text |
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| 1231 | * @since 1.23 |
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| 1232 | */ |
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| 1233 | public function buildGroupConcatField( $delim, $table, $field, $conds = '', |
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| 1247 | |||
| 1248 | /** |
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| 1249 | * Returns an associative array for fields that are of type varbinary, binary, or image |
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| 1250 | * $table can be either a raw table name or passed through tableName() first |
||
| 1251 | * @param string $table |
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| 1252 | * @return array |
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| 1253 | */ |
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| 1254 | View Code Duplication | private function getBinaryColumns( $table ) { |
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| 1266 | |||
| 1267 | /** |
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| 1268 | * @param string $table |
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| 1269 | * @return array |
||
| 1270 | */ |
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| 1271 | View Code Duplication | private function getBitColumns( $table ) { |
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| 1283 | |||
| 1284 | private function populateColumnCaches() { |
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| 1302 | |||
| 1303 | /** |
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| 1304 | * @param string $name |
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| 1305 | * @param string $format |
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| 1306 | * @return string |
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| 1307 | */ |
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| 1308 | function tableName( $name, $format = 'quoted' ) { |
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| 1309 | # Replace reserved words with better ones |
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| 1310 | switch ( $name ) { |
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| 1311 | case 'user': |
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| 1312 | return $this->realTableName( 'mwuser', $format ); |
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| 1313 | default: |
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| 1314 | return $this->realTableName( $name, $format ); |
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| 1315 | } |
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| 1316 | } |
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| 1317 | |||
| 1318 | /** |
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| 1319 | * call this instead of tableName() in the updater when renaming tables |
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| 1320 | * @param string $name |
||
| 1321 | * @param string $format One of quoted, raw, or split |
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| 1322 | * @return string |
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| 1323 | */ |
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| 1324 | function realTableName( $name, $format = 'quoted' ) { |
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| 1336 | |||
| 1337 | /** |
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| 1338 | * Delete a table |
||
| 1339 | * @param string $tableName |
||
| 1340 | * @param string $fName |
||
| 1341 | * @return bool|ResultWrapper |
||
| 1342 | * @since 1.18 |
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| 1343 | */ |
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| 1344 | View Code Duplication | public function dropTable( $tableName, $fName = __METHOD__ ) { |
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| 1354 | |||
| 1355 | /** |
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| 1356 | * Called in the installer and updater. |
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| 1357 | * Probably doesn't need to be called anywhere else in the codebase. |
||
| 1358 | * @param bool|null $value |
||
| 1359 | * @return bool|null |
||
| 1360 | */ |
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| 1361 | public function prepareStatements( $value = null ) { |
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| 1364 | |||
| 1365 | /** |
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| 1366 | * Called in the installer and updater. |
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| 1367 | * Probably doesn't need to be called anywhere else in the codebase. |
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| 1368 | * @param bool|null $value |
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| 1369 | * @return bool|null |
||
| 1370 | */ |
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| 1371 | public function scrollableCursor( $value = null ) { |
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| 1374 | |||
| 1375 | /** |
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| 1376 | * Called in the installer and updater. |
||
| 1377 | * Probably doesn't need to be called anywhere else in the codebase. |
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| 1378 | * @param array|null $value |
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| 1379 | * @return array|null |
||
| 1380 | */ |
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| 1381 | public function ignoreErrors( array $value = null ) { |
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| 1384 | } // end DatabaseMssql class |
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| 1385 |
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If you define a variable conditionally, it can happen that it is not defined for all execution paths.
Let’s take a look at an example:
In the above example, the variable $x is defined if you pass “foo” or “bar” as argument for $a. However, since the switch statement has no default case statement, if you pass any other value, the variable $x would be undefined.
Available Fixes
Check for existence of the variable explicitly:
Define a default value for the variable:
Add a value for the missing path: