Complex classes like DataQuery 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 DataQuery, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 14 | class DataQuery { |
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| 15 | |||
| 16 | /** |
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| 17 | * @var string |
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| 18 | */ |
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| 19 | protected $dataClass; |
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| 20 | |||
| 21 | /** |
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| 22 | * @var SQLQuery |
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| 23 | */ |
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| 24 | protected $query; |
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| 25 | |||
| 26 | /** |
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| 27 | * @var array |
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| 28 | */ |
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| 29 | protected $collidingFields = array(); |
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| 30 | |||
| 31 | private $queriedColumns = null; |
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| 32 | |||
| 33 | /** |
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| 34 | * @var Boolean |
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| 35 | */ |
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| 36 | private $queryFinalised = false; |
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| 37 | |||
| 38 | // TODO: replace subclass_access with this |
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| 39 | protected $querySubclasses = true; |
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| 40 | // TODO: replace restrictclasses with this |
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| 41 | protected $filterByClassName = true; |
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| 42 | |||
| 43 | /** |
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| 44 | * Create a new DataQuery. |
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| 45 | * |
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| 46 | * @param String The name of the DataObject class that you wish to query |
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| 47 | */ |
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| 48 | public function __construct($dataClass) { |
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| 52 | |||
| 53 | /** |
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| 54 | * Clone this object |
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| 55 | */ |
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| 56 | public function __clone() { |
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| 59 | |||
| 60 | /** |
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| 61 | * Return the {@link DataObject} class that is being queried. |
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| 62 | */ |
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| 63 | public function dataClass() { |
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| 66 | |||
| 67 | /** |
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| 68 | * Return the {@link SQLQuery} object that represents the current query; note that it will |
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| 69 | * be a clone of the object. |
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| 70 | */ |
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| 71 | public function query() { |
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| 74 | |||
| 75 | |||
| 76 | /** |
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| 77 | * Remove a filter from the query |
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| 78 | */ |
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| 79 | public function removeFilterOn($fieldExpression) { |
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| 99 | |||
| 100 | /** |
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| 101 | * Set up the simplest initial query |
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| 102 | */ |
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| 103 | public function initialiseQuery() { |
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| 135 | |||
| 136 | public function setQueriedColumns($queriedColumns) { |
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| 139 | |||
| 140 | /** |
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| 141 | * Ensure that the query is ready to execute. |
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| 142 | * |
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| 143 | * @return SQLQuery |
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| 144 | */ |
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| 145 | public function getFinalisedQuery($queriedColumns = null) { |
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| 246 | |||
| 247 | /** |
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| 248 | * Ensure that if a query has an order by clause, those columns are present in the select. |
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| 249 | * |
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| 250 | * @param SQLQuery $query |
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| 251 | * @return null |
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| 252 | */ |
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| 253 | protected function ensureSelectContainsOrderbyColumns($query, $originalSelect = array()) { |
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| 322 | |||
| 323 | /** |
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| 324 | * Execute the query and return the result as {@link Query} object. |
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| 325 | */ |
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| 326 | public function execute() { |
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| 329 | |||
| 330 | /** |
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| 331 | * Return this query's SQL |
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| 332 | */ |
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| 333 | public function sql() { |
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| 336 | |||
| 337 | /** |
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| 338 | * Return the number of records in this query. |
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| 339 | * Note that this will issue a separate SELECT COUNT() query. |
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| 340 | */ |
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| 341 | public function count() { |
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| 345 | |||
| 346 | /** |
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| 347 | * Return the maximum value of the given field in this DataList |
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| 348 | * |
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| 349 | * @param String $field Unquoted database column name (will be escaped automatically) |
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| 350 | */ |
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| 351 | public function max($field) { |
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| 354 | |||
| 355 | /** |
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| 356 | * Return the minimum value of the given field in this DataList |
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| 357 | * |
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| 358 | * @param String $field Unquoted database column name (will be escaped automatically) |
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| 359 | */ |
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| 360 | public function min($field) { |
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| 363 | |||
| 364 | /** |
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| 365 | * Return the average value of the given field in this DataList |
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| 366 | * |
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| 367 | * @param String $field Unquoted database column name (will be escaped automatically) |
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| 368 | */ |
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| 369 | public function avg($field) { |
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| 372 | |||
| 373 | /** |
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| 374 | * Return the sum of the values of the given field in this DataList |
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| 375 | * |
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| 376 | * @param String $field Unquoted database column name (will be escaped automatically) |
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| 377 | */ |
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| 378 | public function sum($field) { |
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| 381 | |||
| 382 | /** |
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| 383 | * Runs a raw aggregate expression. Please handle escaping yourself |
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| 384 | */ |
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| 385 | public function aggregate($expression) { |
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| 388 | |||
| 389 | /** |
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| 390 | * Return the first row that would be returned by this full DataQuery |
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| 391 | * Note that this will issue a separate SELECT ... LIMIT 1 query. |
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| 392 | */ |
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| 393 | public function firstRow() { |
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| 396 | |||
| 397 | /** |
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| 398 | * Return the last row that would be returned by this full DataQuery |
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| 399 | * Note that this will issue a separate SELECT ... LIMIT query. |
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| 400 | */ |
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| 401 | public function lastRow() { |
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| 404 | |||
| 405 | /** |
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| 406 | * Update the SELECT clause of the query with the columns from the given table |
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| 407 | */ |
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| 408 | protected function selectColumnsFromTable(SQLQuery &$query, $tableClass, $columns = null) { |
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| 431 | |||
| 432 | /** |
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| 433 | * Append a GROUP BY clause to this query. |
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| 434 | * |
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| 435 | * @param String $groupby Escaped SQL statement |
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| 436 | */ |
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| 437 | public function groupby($groupby) { |
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| 441 | |||
| 442 | /** |
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| 443 | * Append a HAVING clause to this query. |
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| 444 | * |
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| 445 | * @param String $having Escaped SQL statement |
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| 446 | */ |
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| 447 | public function having($having) { |
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| 451 | |||
| 452 | /** |
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| 453 | * Create a disjunctive subgroup. |
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| 454 | * |
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| 455 | * That is a subgroup joined by OR |
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| 456 | * |
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| 457 | * @return DataQuery_SubGroup |
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| 458 | */ |
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| 459 | public function disjunctiveGroup() { |
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| 462 | |||
| 463 | /** |
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| 464 | * Create a conjunctive subgroup |
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| 465 | * |
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| 466 | * That is a subgroup joined by AND |
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| 467 | * |
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| 468 | * @return DataQuery_SubGroup |
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| 469 | */ |
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| 470 | public function conjunctiveGroup() { |
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| 473 | |||
| 474 | /** |
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| 475 | * Append a WHERE clause to this query. |
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| 476 | * There are two different ways of doing this: |
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| 477 | * |
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| 478 | * <code> |
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| 479 | * // the entire predicate as a single string |
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| 480 | * $query->where("\"Column\" = 'Value'"); |
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| 481 | * |
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| 482 | * // multiple predicates as an array |
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| 483 | * $query->where(array("\"Column\" = 'Value'", "\"Column\" != 'Value'")); |
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| 484 | * </code> |
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| 485 | * |
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| 486 | * @param string|array $where Predicate(s) to set, as escaped SQL statements. |
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| 487 | */ |
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| 488 | public function where($filter) { |
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| 494 | |||
| 495 | /** |
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| 496 | * Append a WHERE with OR. |
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| 497 | * |
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| 498 | * @example $dataQuery->whereAny(array("\"Monkey\" = 'Chimp'", "\"Color\" = 'Brown'")); |
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| 499 | * @see where() |
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| 500 | * |
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| 501 | * @param array $filter Escaped SQL statement. |
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| 502 | * @return DataQuery |
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| 503 | */ |
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| 504 | public function whereAny($filter) { |
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| 510 | |||
| 511 | /** |
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| 512 | * Set the ORDER BY clause of this query |
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| 513 | * |
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| 514 | * @see SQLQuery::orderby() |
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| 515 | * |
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| 516 | * @param String $sort Column to sort on (escaped SQL statement) |
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| 517 | * @param String $direction Direction ("ASC" or "DESC", escaped SQL statement) |
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| 518 | * @param Boolean $clear Clear existing values |
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| 519 | * @return DataQuery |
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| 520 | */ |
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| 521 | public function sort($sort = null, $direction = null, $clear = true) { |
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| 530 | |||
| 531 | /** |
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| 532 | * Reverse order by clause |
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| 533 | * |
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| 534 | * @return DataQuery |
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| 535 | */ |
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| 536 | public function reverseSort() { |
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| 540 | |||
| 541 | /** |
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| 542 | * Set the limit of this query. |
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| 543 | * |
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| 544 | * @param int $limit |
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| 545 | * @param int $offset |
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| 546 | */ |
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| 547 | public function limit($limit, $offset = 0) { |
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| 551 | |||
| 552 | /** |
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| 553 | * Set whether this query should be distinct or not. |
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| 554 | * |
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| 555 | * @param bool $value |
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| 556 | * @return DataQuery |
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| 557 | */ |
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| 558 | public function distinct($value) { |
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| 562 | |||
| 563 | /** |
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| 564 | * Add an INNER JOIN clause to this query. |
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| 565 | * |
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| 566 | * @param String $table The unquoted table name to join to. |
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| 567 | * @param String $onClause The filter for the join (escaped SQL statement) |
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| 568 | * @param String $alias An optional alias name (unquoted) |
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| 569 | */ |
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| 570 | public function innerJoin($table, $onClause, $alias = null) { |
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| 576 | |||
| 577 | /** |
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| 578 | * Add a LEFT JOIN clause to this query. |
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| 579 | * |
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| 580 | * @param String $table The unquoted table to join to. |
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| 581 | * @param String $onClause The filter for the join (escaped SQL statement). |
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| 582 | * @param String $alias An optional alias name (unquoted) |
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| 583 | */ |
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| 584 | public function leftJoin($table, $onClause, $alias = null) { |
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| 590 | |||
| 591 | /** |
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| 592 | * Traverse the relationship fields, and add the table |
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| 593 | * mappings to the query object state. This has to be called |
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| 594 | * in any overloaded {@link SearchFilter->apply()} methods manually. |
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| 595 | * |
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| 596 | * @param String|array $relation The array/dot-syntax relation to follow |
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| 597 | * @return The model class of the related item |
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| 598 | */ |
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| 599 | public function applyRelation($relation) { |
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| 673 | |||
| 674 | /** |
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| 675 | * Removes the result of query from this query. |
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| 676 | * |
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| 677 | * @param DataQuery $subtractQuery |
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| 678 | * @param string $field |
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| 679 | */ |
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| 680 | public function subtract(DataQuery $subtractQuery, $field='ID') { |
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| 690 | |||
| 691 | /** |
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| 692 | * Select the given fields from the given table. |
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| 693 | * |
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| 694 | * @param String $table Unquoted table name (will be escaped automatically) |
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| 695 | * @param Array $fields Database column names (will be escaped automatically) |
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| 696 | */ |
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| 697 | public function selectFromTable($table, $fields) { |
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| 706 | |||
| 707 | /** |
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| 708 | * Query the given field column from the database and return as an array. |
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| 709 | * |
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| 710 | * @param string $field See {@link expressionForField()}. |
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| 711 | * @return array List of column values for the specified column |
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| 712 | */ |
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| 713 | public function column($field = 'ID') { |
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| 723 | |||
| 724 | /** |
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| 725 | * @param String $field Select statement identifier, either the unquoted column name, |
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| 726 | * the full composite SQL statement, or the alias set through {@link SQLQuery->selectField()}. |
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| 727 | * @return String The expression used to query this field via this DataQuery |
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| 728 | */ |
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| 729 | protected function expressionForField($field) { |
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| 744 | |||
| 745 | /** |
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| 746 | * Select the given field expressions. |
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| 747 | * |
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| 748 | * @param $fieldExpression String The field to select (escaped SQL statement) |
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| 749 | * @param $alias String The alias of that field (escaped SQL statement) |
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| 750 | */ |
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| 751 | protected function selectField($fieldExpression, $alias = null) { |
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| 754 | |||
| 755 | //// QUERY PARAMS |
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| 756 | |||
| 757 | /** |
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| 758 | * An arbitrary store of query parameters that can be used by decorators. |
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| 759 | * @todo This will probably be made obsolete if we have subclasses of DataList and/or DataQuery. |
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| 760 | */ |
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| 761 | private $queryParams; |
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| 762 | |||
| 763 | /** |
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| 764 | * Set an arbitrary query parameter, that can be used by decorators to add additional meta-data to the query. |
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| 765 | * It's expected that the $key will be namespaced, e.g, 'Versioned.stage' instead of just 'stage'. |
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| 766 | */ |
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| 767 | public function setQueryParam($key, $value) { |
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| 770 | |||
| 771 | /** |
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| 772 | * Set an arbitrary query parameter, that can be used by decorators to add additional meta-data to the query. |
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| 773 | */ |
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| 774 | public function getQueryParam($key) { |
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| 778 | |||
| 779 | /** |
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| 780 | * Returns all query parameters |
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| 781 | * @return array query parameters array |
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| 782 | */ |
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| 783 | public function getQueryParams() { |
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| 786 | } |
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| 787 | |||
| 867 |
This check marks implicit conversions of arrays to boolean values in a comparison. While in PHP an empty array is considered to be equal (but not identical) to false, this is not always apparent.
Consider making the comparison explicit by using
empty(..)or! empty(...)instead.