vendor/doctrine/orm/lib/Doctrine/ORM/Tools/Pagination/CountOutputWalker.php

   1 <?php
   2 /**
   3  * Doctrine ORM
   4  *
   5  * LICENSE
   6  *
   7  * This source file is subject to the new BSD license that is bundled
   8  * with this package in the file LICENSE.txt.
   9  * If you did not receive a copy of the license and are unable to
  10  * obtain it through the world-wide-web, please send an email
  11  * to kontakt@beberlei.de so I can send you a copy immediately.
  12  */
  13
  14 namespace Doctrine\ORM\Tools\Pagination;
  15
  16 use Doctrine\ORM\Query\SqlWalker;
  17 use Doctrine\ORM\Query\AST\SelectStatement;
  18
  19 /**
  20  * Wraps the query in order to accurately count the root objects.
  21  *
  22  * Given a DQL like `SELECT u FROM User u` it will generate an SQL query like:
  23  * SELECT COUNT(*) (SELECT DISTINCT <id> FROM (<original SQL>))
  24  *
  25  * Works with composite keys but cannot deal with queries that have multiple
  26  * root entities (e.g. `SELECT f, b from Foo, Bar`)
  27  *
  28  * @author Sander Marechal <s.marechal@jejik.com>
  29  */
  30 class CountOutputWalker extends SqlWalker
  31 {
  32     /**
  33      * @var \Doctrine\DBAL\Platforms\AbstractPlatform
  34      */
  35     private $platform;
  36
  37     /**
  38      * @var \Doctrine\ORM\Query\ResultSetMapping
  39      */
  40     private $rsm;
  41
  42     /**
  43      * @var array
  44      */
  45     private $queryComponents;
  46
  47     /**
  48      * Constructor.
  49      *
  50      * Stores various parameters that are otherwise unavailable
  51      * because Doctrine\ORM\Query\SqlWalker keeps everything private without
  52      * accessors.
  53      *
  54      * @param \Doctrine\ORM\Query              $query
  55      * @param \Doctrine\ORM\Query\ParserResult $parserResult
  56      * @param array                            $queryComponents
  57      */
  58     public function __construct($query, $parserResult, array $queryComponents)
  59     {
  60         $this->platform = $query->getEntityManager()->getConnection()->getDatabasePlatform();
  61         $this->rsm = $parserResult->getResultSetMapping();
  62         $this->queryComponents = $queryComponents;
  63
  64         parent::__construct($query, $parserResult, $queryComponents);
  65     }
  66
  67     /**
  68      * Walks down a SelectStatement AST node, wrapping it in a COUNT (SELECT DISTINCT).
  69      *
  70      * Note that the ORDER BY clause is not removed. Many SQL implementations (e.g. MySQL)
  71      * are able to cache subqueries. By keeping the ORDER BY clause intact, the limitSubQuery
  72      * that will most likely be executed next can be read from the native SQL cache.
  73      *
  74      * @param SelectStatement $AST
  75      *
  76      * @return string
  77      *
  78      * @throws \RuntimeException
  79      */
  80     public function walkSelectStatement(SelectStatement $AST)
  81     {
  82         if ($this->platform->getName() === "mssql") {
  83             $AST->orderByClause = null;
  84         }
  85
  86         $sql = parent::walkSelectStatement($AST);
  87
  88         if ($AST->groupByClause) {
  89             return sprintf(
  90                 'SELECT %s AS dctrn_count FROM (%s) dctrn_table',
  91                 $this->platform->getCountExpression('*'),
  92                 $sql
  93             );
  94         }
  95
  96         // Find out the SQL alias of the identifier column of the root entity
  97         // It may be possible to make this work with multiple root entities but that
  98         // would probably require issuing multiple queries or doing a UNION SELECT
  99         // so for now, It's not supported.
 100
 101         // Get the root entity and alias from the AST fromClause
 102         $from = $AST->fromClause->identificationVariableDeclarations;
 103         if (count($from) > 1) {
 104             throw new \RuntimeException("Cannot count query which selects two FROM components, cannot make distinction");
 105         }
 106
 107         $fromRoot       = reset($from);
 108         $rootAlias      = $fromRoot->rangeVariableDeclaration->aliasIdentificationVariable;
 109         $rootClass      = $this->queryComponents[$rootAlias]['metadata'];
 110         $rootIdentifier = $rootClass->identifier;
 111
 112         // For every identifier, find out the SQL alias by combing through the ResultSetMapping
 113         $sqlIdentifier = array();
 114         foreach ($rootIdentifier as $property) {
 115             if (isset($rootClass->fieldMappings[$property])) {
 116                 foreach (array_keys($this->rsm->fieldMappings, $property) as $alias) {
 117                     if ($this->rsm->columnOwnerMap[$alias] == $rootAlias) {
 118                         $sqlIdentifier[$property] = $alias;
 119                     }
 120                 }
 121             }
 122
 123             if (isset($rootClass->associationMappings[$property])) {
 124                 $joinColumn = $rootClass->associationMappings[$property]['joinColumns'][0]['name'];
 125
 126                 foreach (array_keys($this->rsm->metaMappings, $joinColumn) as $alias) {
 127                     if ($this->rsm->columnOwnerMap[$alias] == $rootAlias) {
 128                         $sqlIdentifier[$property] = $alias;
 129                     }
 130                 }
 131             }
 132         }
 133
 134         if (count($rootIdentifier) != count($sqlIdentifier)) {
 135             throw new \RuntimeException(sprintf(
 136                 'Not all identifier properties can be found in the ResultSetMapping: %s',
 137                 implode(', ', array_diff($rootIdentifier, array_keys($sqlIdentifier)))
 138             ));
 139         }
 140
 141         // Build the counter query
 142         return sprintf('SELECT %s AS dctrn_count FROM (SELECT DISTINCT %s FROM (%s) dctrn_result) dctrn_table',
 143             $this->platform->getCountExpression('*'),
 144             implode(', ', $sqlIdentifier),
 145             $sql
 146         );
 147     }
 148 }