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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| 21 | class DataQuery |
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| 22 | { |
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| 23 | |||
| 24 | /** |
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| 25 | * @var string |
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| 26 | */ |
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| 27 | protected $dataClass; |
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| 28 | |||
| 29 | /** |
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| 30 | * @var SQLSelect |
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| 31 | */ |
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| 32 | protected $query; |
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| 33 | |||
| 34 | /** |
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| 35 | * Map of all field names to an array of conflicting column SQL |
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| 36 | * |
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| 37 | * E.g. |
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| 38 | * array( |
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| 39 | * 'Title' => array( |
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| 40 | * '"MyTable"."Title"', |
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| 41 | * '"AnotherTable"."Title"', |
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| 42 | * ) |
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| 43 | * ) |
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| 44 | * |
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| 45 | * @var array |
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| 46 | */ |
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| 47 | protected $collidingFields = array(); |
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| 48 | |||
| 49 | /** |
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| 50 | * Allows custom callback to be registered before getFinalisedQuery is called. |
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| 51 | * |
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| 52 | * @var DataQueryManipulator[] |
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| 53 | */ |
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| 54 | protected $dataQueryManipulators = []; |
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| 55 | |||
| 56 | private $queriedColumns = null; |
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| 57 | |||
| 58 | /** |
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| 59 | * @var bool |
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| 60 | */ |
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| 61 | private $queryFinalised = false; |
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| 62 | |||
| 63 | // TODO: replace subclass_access with this |
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| 64 | protected $querySubclasses = true; |
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| 65 | // TODO: replace restrictclasses with this |
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| 66 | protected $filterByClassName = true; |
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| 67 | |||
| 68 | /** |
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| 69 | * Create a new DataQuery. |
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| 70 | * |
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| 71 | * @param string $dataClass The name of the DataObject class that you wish to query |
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| 72 | */ |
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| 73 | public function __construct($dataClass) |
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| 78 | |||
| 79 | /** |
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| 80 | * Clone this object |
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| 81 | */ |
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| 82 | public function __clone() |
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| 86 | |||
| 87 | /** |
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| 88 | * Return the {@link DataObject} class that is being queried. |
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| 89 | * |
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| 90 | * @return string |
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| 91 | */ |
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| 92 | public function dataClass() |
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| 96 | |||
| 97 | /** |
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| 98 | * Return the {@link SQLSelect} object that represents the current query; note that it will |
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| 99 | * be a clone of the object. |
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| 100 | * |
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| 101 | * @return SQLSelect |
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| 102 | */ |
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| 103 | public function query() |
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| 107 | |||
| 108 | |||
| 109 | /** |
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| 110 | * Remove a filter from the query |
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| 111 | * |
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| 112 | * @param string|array $fieldExpression The predicate of the condition to remove |
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| 113 | * (ignoring parameters). The expression will be considered a match if it's |
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| 114 | * contained within any other predicate. |
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| 115 | * @return DataQuery Self reference |
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| 116 | */ |
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| 117 | public function removeFilterOn($fieldExpression) |
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| 158 | |||
| 159 | /** |
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| 160 | * Set up the simplest initial query |
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| 161 | */ |
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| 162 | protected function initialiseQuery() |
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| 184 | |||
| 185 | public function setQueriedColumns($queriedColumns) |
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| 189 | |||
| 190 | /** |
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| 191 | * Ensure that the query is ready to execute. |
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| 192 | * |
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| 193 | * @param array|null $queriedColumns Any columns to filter the query by |
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| 194 | * @return SQLSelect The finalised sql query |
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| 195 | */ |
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| 196 | public function getFinalisedQuery($queriedColumns = null) |
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| 341 | |||
| 342 | /** |
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| 343 | * Ensure that if a query has an order by clause, those columns are present in the select. |
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| 344 | * |
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| 345 | * @param SQLSelect $query |
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| 346 | * @param array $originalSelect |
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| 347 | */ |
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| 348 | protected function ensureSelectContainsOrderbyColumns($query, $originalSelect = array()) |
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| 411 | |||
| 412 | /** |
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| 413 | * Execute the query and return the result as {@link SS_Query} object. |
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| 414 | * |
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| 415 | * @return Query |
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| 416 | */ |
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| 417 | public function execute() |
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| 421 | |||
| 422 | /** |
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| 423 | * Return this query's SQL |
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| 424 | * |
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| 425 | * @param array $parameters Out variable for parameters required for this query |
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| 426 | * @return string The resulting SQL query (may be paramaterised) |
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| 427 | */ |
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| 428 | public function sql(&$parameters = array()) |
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| 432 | |||
| 433 | /** |
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| 434 | * Return the number of records in this query. |
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| 435 | * Note that this will issue a separate SELECT COUNT() query. |
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| 436 | * |
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| 437 | * @return int |
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| 438 | */ |
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| 439 | public function count() |
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| 444 | |||
| 445 | /** |
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| 446 | * Return the maximum value of the given field in this DataList |
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| 447 | * |
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| 448 | * @param String $field Unquoted database column name. Will be ANSI quoted |
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| 449 | * automatically so must not contain double quotes. |
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| 450 | * @return string |
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| 451 | */ |
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| 452 | public function max($field) |
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| 460 | |||
| 461 | /** |
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| 462 | * Return the minimum value of the given field in this DataList |
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| 463 | * |
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| 464 | * @param string $field Unquoted database column name. Will be ANSI quoted |
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| 465 | * automatically so must not contain double quotes. |
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| 466 | * @return string |
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| 467 | */ |
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| 468 | public function min($field) |
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| 476 | |||
| 477 | /** |
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| 478 | * Return the average value of the given field in this DataList |
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| 479 | * |
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| 480 | * @param string $field Unquoted database column name. Will be ANSI quoted |
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| 481 | * automatically so must not contain double quotes. |
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| 482 | * @return string |
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| 483 | */ |
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| 484 | public function avg($field) |
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| 492 | |||
| 493 | /** |
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| 494 | * Return the sum of the values of the given field in this DataList |
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| 495 | * |
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| 496 | * @param string $field Unquoted database column name. Will be ANSI quoted |
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| 497 | * automatically so must not contain double quotes. |
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| 498 | * @return string |
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| 499 | */ |
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| 500 | public function sum($field) |
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| 508 | |||
| 509 | /** |
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| 510 | * Runs a raw aggregate expression. Please handle escaping yourself |
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| 511 | * |
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| 512 | * @param string $expression An aggregate expression, such as 'MAX("Balance")', or a set of them |
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| 513 | * (as an escaped SQL statement) |
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| 514 | * @return string |
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| 515 | */ |
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| 516 | public function aggregate($expression) |
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| 520 | |||
| 521 | /** |
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| 522 | * Return the first row that would be returned by this full DataQuery |
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| 523 | * Note that this will issue a separate SELECT ... LIMIT 1 query. |
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| 524 | */ |
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| 525 | public function firstRow() |
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| 529 | |||
| 530 | /** |
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| 531 | * Return the last row that would be returned by this full DataQuery |
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| 532 | * Note that this will issue a separate SELECT ... LIMIT query. |
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| 533 | */ |
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| 534 | public function lastRow() |
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| 538 | |||
| 539 | /** |
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| 540 | * Update the SELECT clause of the query with the columns from the given table |
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| 541 | * |
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| 542 | * @param SQLSelect $query |
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| 543 | * @param string $tableClass Class to select from |
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| 544 | * @param array $columns |
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| 545 | */ |
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| 546 | protected function selectColumnsFromTable(SQLSelect &$query, $tableClass, $columns = null) |
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| 577 | |||
| 578 | /** |
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| 579 | * Append a GROUP BY clause to this query. |
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| 580 | * |
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| 581 | * @param string $groupby Escaped SQL statement |
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| 582 | * @return $this |
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| 583 | */ |
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| 584 | public function groupby($groupby) |
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| 589 | |||
| 590 | /** |
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| 591 | * Append a HAVING clause to this query. |
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| 592 | * |
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| 593 | * @param string $having Escaped SQL statement |
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| 594 | * @return $this |
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| 595 | */ |
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| 596 | public function having($having) |
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| 601 | |||
| 602 | /** |
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| 603 | * Create a disjunctive subgroup. |
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| 604 | * |
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| 605 | * That is a subgroup joined by OR |
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| 606 | * |
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| 607 | * @return DataQuery_SubGroup |
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| 608 | */ |
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| 609 | public function disjunctiveGroup() |
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| 613 | |||
| 614 | /** |
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| 615 | * Create a conjunctive subgroup |
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| 616 | * |
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| 617 | * That is a subgroup joined by AND |
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| 618 | * |
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| 619 | * @return DataQuery_SubGroup |
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| 620 | */ |
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| 621 | public function conjunctiveGroup() |
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| 625 | |||
| 626 | /** |
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| 627 | * Adds a WHERE clause. |
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| 628 | * |
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| 629 | * @see SQLSelect::addWhere() for syntax examples, although DataQuery |
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| 630 | * won't expand multiple arguments as SQLSelect does. |
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| 631 | * |
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| 632 | * @param string|array|SQLConditionGroup $filter Predicate(s) to set, as escaped SQL statements or |
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| 633 | * paramaterised queries |
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| 634 | * @return DataQuery |
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| 635 | */ |
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| 636 | public function where($filter) |
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| 643 | |||
| 644 | /** |
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| 645 | * Append a WHERE with OR. |
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| 646 | * |
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| 647 | * @see SQLSelect::addWhere() for syntax examples, although DataQuery |
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| 648 | * won't expand multiple method arguments as SQLSelect does. |
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| 649 | * |
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| 650 | * @param string|array|SQLConditionGroup $filter Predicate(s) to set, as escaped SQL statements or |
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| 651 | * paramaterised queries |
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| 652 | * @return DataQuery |
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| 653 | */ |
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| 654 | public function whereAny($filter) |
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| 661 | |||
| 662 | /** |
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| 663 | * Set the ORDER BY clause of this query |
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| 664 | * |
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| 665 | * @see SQLSelect::orderby() |
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| 666 | * |
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| 667 | * @param String $sort Column to sort on (escaped SQL statement) |
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| 668 | * @param String $direction Direction ("ASC" or "DESC", escaped SQL statement) |
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| 669 | * @param Boolean $clear Clear existing values |
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| 670 | * @return DataQuery |
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| 671 | */ |
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| 672 | public function sort($sort = null, $direction = null, $clear = true) |
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| 682 | |||
| 683 | /** |
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| 684 | * Reverse order by clause |
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| 685 | * |
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| 686 | * @return DataQuery |
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| 687 | */ |
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| 688 | public function reverseSort() |
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| 693 | |||
| 694 | /** |
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| 695 | * Set the limit of this query. |
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| 696 | * |
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| 697 | * @param int $limit |
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| 698 | * @param int $offset |
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| 699 | * @return $this |
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| 700 | */ |
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| 701 | public function limit($limit, $offset = 0) |
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| 706 | |||
| 707 | /** |
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| 708 | * Set whether this query should be distinct or not. |
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| 709 | * |
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| 710 | * @param bool $value |
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| 711 | * @return DataQuery |
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| 712 | */ |
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| 713 | public function distinct($value) |
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| 718 | |||
| 719 | /** |
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| 720 | * Add an INNER JOIN clause to this query. |
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| 721 | * |
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| 722 | * @param String $table The unquoted table name to join to. |
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| 723 | * @param String $onClause The filter for the join (escaped SQL statement) |
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| 724 | * @param String $alias An optional alias name (unquoted) |
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| 725 | * @param int $order A numerical index to control the order that joins are added to the query; lower order values |
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| 726 | * will cause the query to appear first. The default is 20, and joins created automatically by the |
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| 727 | * ORM have a value of 10. |
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| 728 | * @param array $parameters Any additional parameters if the join is a parameterised subquery |
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| 729 | * @return $this |
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| 730 | */ |
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| 731 | public function innerJoin($table, $onClause, $alias = null, $order = 20, $parameters = array()) |
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| 738 | |||
| 739 | /** |
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| 740 | * Add a LEFT JOIN clause to this query. |
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| 741 | * |
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| 742 | * @param string $table The unquoted table to join to. |
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| 743 | * @param string $onClause The filter for the join (escaped SQL statement). |
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| 744 | * @param string $alias An optional alias name (unquoted) |
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| 745 | * @param int $order A numerical index to control the order that joins are added to the query; lower order values |
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| 746 | * will cause the query to appear first. The default is 20, and joins created automatically by the |
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| 747 | * ORM have a value of 10. |
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| 748 | * @param array $parameters Any additional parameters if the join is a parameterised subquery |
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| 749 | * @return $this |
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| 750 | */ |
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| 751 | public function leftJoin($table, $onClause, $alias = null, $order = 20, $parameters = array()) |
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| 758 | |||
| 759 | /** |
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| 760 | * Prefix of all joined table aliases. E.g. ->filter('Banner.Image.Title)' |
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| 761 | * Will join the Banner, and then Image relations |
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| 762 | * `$relationPrefx` will be `banner_image_` |
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| 763 | * Each table in the Image chain will be suffixed to this prefix. E.g. |
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| 764 | * `banner_image_File` and `banner_image_Image` |
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| 765 | * |
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| 766 | * This will be null if no relation is joined. |
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| 767 | * E.g. `->filter('Title')` |
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| 768 | * |
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| 769 | * @param string|array $relation Relation in '.' delimited string, or array of parts |
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| 770 | * @return string Table prefix |
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| 771 | */ |
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| 772 | public static function applyRelationPrefix($relation) |
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| 782 | |||
| 783 | /** |
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| 784 | * Traverse the relationship fields, and add the table |
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| 785 | * mappings to the query object state. This has to be called |
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| 786 | * in any overloaded {@link SearchFilter->apply()} methods manually. |
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| 787 | * |
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| 788 | * Note, that in order to filter against the joined relation user code must |
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| 789 | * use {@see tablePrefix()} to get the table alias used for this relation. |
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| 790 | * |
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| 791 | * @param string|array $relation The array/dot-syntax relation to follow |
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| 792 | * @param bool $linearOnly Set to true to restrict to linear relations only. Set this |
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| 793 | * if this relation will be used for sorting, and should not include duplicate rows. |
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| 794 | * @return string The model class of the related item |
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| 795 | */ |
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| 796 | public function applyRelation($relation, $linearOnly = false) |
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| 871 | |||
| 872 | /** |
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| 873 | * Join the given has_many relation to this query. |
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| 874 | * Also works with belongs_to |
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| 875 | * |
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| 876 | * Doesn't work with polymorphic relationships |
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| 877 | * |
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| 878 | * @param string $localClass Name of class that has the has_many to the joined class |
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| 879 | * @param string $localField Name of the has_many relationship to join |
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| 880 | * @param string $foreignClass Class to join |
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| 881 | * @param string $localPrefix Table prefix for parent class |
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| 882 | * @param string $foreignPrefix Table prefix to use |
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| 883 | * @param string $type 'has_many' or 'belongs_to' |
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| 884 | */ |
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| 885 | protected function joinHasManyRelation( |
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| 942 | |||
| 943 | /** |
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| 944 | * Join the given class to this query with the given key |
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| 945 | * |
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| 946 | * @param string $localClass Name of class that has the has_one to the joined class |
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| 947 | * @param string $localField Name of the has_one relationship to joi |
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| 948 | * @param string $foreignClass Class to join |
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| 949 | * @param string $localPrefix Table prefix to use for local class |
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| 950 | * @param string $foreignPrefix Table prefix to use for joined table |
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| 951 | */ |
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| 952 | protected function joinHasOneRelation( |
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| 1004 | |||
| 1005 | /** |
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| 1006 | * Join table via many_many relationship |
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| 1007 | * |
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| 1008 | * @param string $relationClass |
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| 1009 | * @param string $parentClass |
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| 1010 | * @param string $componentClass |
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| 1011 | * @param string $parentField |
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| 1012 | * @param string $componentField |
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| 1013 | * @param string $relationClassOrTable Name of relation table |
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| 1014 | * @param string $parentPrefix Table prefix for parent class |
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| 1015 | * @param string $componentPrefix Table prefix to use for both joined and mapping table |
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| 1016 | */ |
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| 1017 | protected function joinManyManyRelationship( |
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| 1074 | |||
| 1075 | /** |
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| 1076 | * Removes the result of query from this query. |
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| 1077 | * |
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| 1078 | * @param DataQuery $subtractQuery |
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| 1079 | * @param string $field |
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| 1080 | * @return $this |
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| 1081 | */ |
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| 1082 | public function subtract(DataQuery $subtractQuery, $field = 'ID') |
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| 1094 | |||
| 1095 | /** |
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| 1096 | * Select the given fields from the given table. |
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| 1097 | * |
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| 1098 | * @param string $table Unquoted table name (will be escaped automatically) |
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| 1099 | * @param array $fields Database column names (will be escaped automatically) |
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| 1100 | * @return $this |
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| 1101 | */ |
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| 1102 | public function selectFromTable($table, $fields) |
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| 1112 | |||
| 1113 | /** |
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| 1114 | * Query the given field column from the database and return as an array. |
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| 1115 | * |
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| 1116 | * @param string $field See {@link expressionForField()}. |
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| 1117 | * @return array List of column values for the specified column |
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| 1118 | */ |
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| 1119 | public function column($field = 'ID') |
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| 1130 | |||
| 1131 | /** |
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| 1132 | * @param String $field Select statement identifier, either the unquoted column name, |
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| 1133 | * the full composite SQL statement, or the alias set through {@link SQLSelect->selectField()}. |
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| 1134 | * @return String The expression used to query this field via this DataQuery |
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| 1135 | */ |
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| 1136 | protected function expressionForField($field) |
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| 1153 | |||
| 1154 | /** |
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| 1155 | * Select the given field expressions. |
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| 1156 | * |
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| 1157 | * @param $fieldExpression String The field to select (escaped SQL statement) |
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| 1158 | * @param $alias String The alias of that field (escaped SQL statement) |
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| 1159 | */ |
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| 1160 | public function selectField($fieldExpression, $alias = null) |
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| 1164 | |||
| 1165 | //// QUERY PARAMS |
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| 1166 | |||
| 1167 | /** |
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| 1168 | * An arbitrary store of query parameters that can be used by decorators. |
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| 1169 | */ |
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| 1170 | private $queryParams; |
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| 1171 | |||
| 1172 | /** |
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| 1173 | * Set an arbitrary query parameter, that can be used by decorators to add additional meta-data to the query. |
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| 1174 | * It's expected that the $key will be namespaced, e.g, 'Versioned.stage' instead of just 'stage'. |
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| 1175 | * |
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| 1176 | * @param string $key |
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| 1177 | * @param string|array $value |
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| 1178 | * @return $this |
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| 1179 | */ |
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| 1180 | public function setQueryParam($key, $value) |
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| 1185 | |||
| 1186 | /** |
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| 1187 | * Set an arbitrary query parameter, that can be used by decorators to add additional meta-data to the query. |
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| 1188 | * |
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| 1189 | * @param string $key |
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| 1190 | * @return string |
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| 1191 | */ |
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| 1192 | public function getQueryParam($key) |
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| 1199 | |||
| 1200 | /** |
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| 1201 | * Returns all query parameters |
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| 1202 | * @return array query parameters array |
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| 1203 | */ |
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| 1204 | public function getQueryParams() |
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| 1208 | |||
| 1209 | /** |
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| 1210 | * Get query manipulators |
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| 1211 | * |
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| 1212 | * @return DataQueryManipulator[] |
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| 1213 | */ |
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| 1214 | public function getDataQueryManipulators() |
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| 1218 | |||
| 1219 | /** |
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| 1220 | * Assign callback to be invoked in getFinalisedQuery() |
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| 1221 | * |
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| 1222 | * @param DataQueryManipulator $manipulator |
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| 1223 | * @return $this |
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| 1224 | */ |
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| 1225 | public function pushQueryManipulator(DataQueryManipulator $manipulator) |
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| 1230 | } |
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| 1231 |
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.