Rajout de doctrine/orm
[zf2.biz/application_blanche.git] / vendor / doctrine / orm / lib / Doctrine / ORM / Query / SqlWalker.php
diff --git a/vendor/doctrine/orm/lib/Doctrine/ORM/Query/SqlWalker.php b/vendor/doctrine/orm/lib/Doctrine/ORM/Query/SqlWalker.php
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+<?php
+/*
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This software consists of voluntary contributions made by many individuals
+ * and is licensed under the MIT license. For more information, see
+ * <http://www.doctrine-project.org>.
+ */
+
+namespace Doctrine\ORM\Query;
+
+use Doctrine\DBAL\LockMode,
+    Doctrine\DBAL\Types\Type,
+    Doctrine\ORM\Mapping\ClassMetadata,
+    Doctrine\ORM\Query,
+    Doctrine\ORM\Query\QueryException,
+    Doctrine\ORM\Mapping\ClassMetadataInfo;
+
+/**
+ * The SqlWalker is a TreeWalker that walks over a DQL AST and constructs
+ * the corresponding SQL.
+ *
+ * @author Guilherme Blanco <guilhermeblanco@hotmail.com>
+ * @author Roman Borschel <roman@code-factory.org>
+ * @author Benjamin Eberlei <kontakt@beberlei.de>
+ * @author Alexander <iam.asm89@gmail.com>
+ * @since  2.0
+ * @todo Rename: SQLWalker
+ */
+class SqlWalker implements TreeWalker
+{
+    /**
+     * @var string
+     */
+    const HINT_DISTINCT = 'doctrine.distinct';
+
+    /**
+     * @var ResultSetMapping
+     */
+    private $rsm;
+
+    /**
+     * Counters for generating unique column aliases.
+     *
+     * @var integer
+     */
+    private $aliasCounter = 0;
+
+    /**
+     * Counters for generating unique table aliases.
+     *
+     * @var integer
+     */
+    private $tableAliasCounter = 0;
+
+    /**
+     * Counters for generating unique scalar result.
+     *
+     * @var integer
+     */
+    private $scalarResultCounter = 1;
+
+    /**
+     * Counters for generating unique parameter indexes.
+     *
+     * @var integer
+     */
+    private $sqlParamIndex = 0;
+
+    /**
+     * @var ParserResult
+     */
+    private $parserResult;
+
+    /**
+     * @var EntityManager
+     */
+    private $em;
+
+    /**
+     * @var \Doctrine\DBAL\Connection
+     */
+    private $conn;
+
+    /**
+     * @var AbstractQuery
+     */
+    private $query;
+
+    /**
+     * @var array
+     */
+    private $tableAliasMap = array();
+
+    /**
+     * Map from result variable names to their SQL column alias names.
+     *
+     * @var array
+     */
+    private $scalarResultAliasMap = array();
+
+    /**
+     * Map from DQL-Alias + Field-Name to SQL Column Alias
+     *
+     * @var array
+     */
+    private $scalarFields = array();
+
+    /**
+     * Map of all components/classes that appear in the DQL query.
+     *
+     * @var array
+     */
+    private $queryComponents;
+
+    /**
+     * A list of classes that appear in non-scalar SelectExpressions.
+     *
+     * @var array
+     */
+    private $selectedClasses = array();
+
+    /**
+     * The DQL alias of the root class of the currently traversed query.
+     * 
+     * @var array
+     */
+    private $rootAliases = array();
+
+    /**
+     * Flag that indicates whether to generate SQL table aliases in the SQL.
+     * These should only be generated for SELECT queries, not for UPDATE/DELETE.
+     *
+     * @var boolean
+     */
+    private $useSqlTableAliases = true;
+
+    /**
+     * The database platform abstraction.
+     *
+     * @var AbstractPlatform
+     */
+    private $platform;
+
+    /**
+     * The quote strategy.
+     *
+     * @var \Doctrine\ORM\Mapping\QuoteStrategy
+     */
+    private $quoteStrategy;
+
+    /**
+     * {@inheritDoc}
+     */
+    public function __construct($query, $parserResult, array $queryComponents)
+    {
+        $this->query            = $query;
+        $this->parserResult     = $parserResult;
+        $this->queryComponents  = $queryComponents;
+        $this->rsm              = $parserResult->getResultSetMapping();
+        $this->em               = $query->getEntityManager();
+        $this->conn             = $this->em->getConnection();
+        $this->platform         = $this->conn->getDatabasePlatform();
+        $this->quoteStrategy    = $this->em->getConfiguration()->getQuoteStrategy();
+    }
+
+    /**
+     * Gets the Query instance used by the walker.
+     *
+     * @return Query.
+     */
+    public function getQuery()
+    {
+        return $this->query;
+    }
+
+    /**
+     * Gets the Connection used by the walker.
+     *
+     * @return Connection
+     */
+    public function getConnection()
+    {
+        return $this->conn;
+    }
+
+    /**
+     * Gets the EntityManager used by the walker.
+     *
+     * @return EntityManager
+     */
+    public function getEntityManager()
+    {
+        return $this->em;
+    }
+
+    /**
+     * Gets the information about a single query component.
+     *
+     * @param string $dqlAlias The DQL alias.
+     * @return array
+     */
+    public function getQueryComponent($dqlAlias)
+    {
+        return $this->queryComponents[$dqlAlias];
+    }
+
+    /**
+     * Gets an executor that can be used to execute the result of this walker.
+     *
+     * @return AbstractExecutor
+     */
+    public function getExecutor($AST)
+    {
+        switch (true) {
+            case ($AST instanceof AST\DeleteStatement):
+                $primaryClass = $this->em->getClassMetadata($AST->deleteClause->abstractSchemaName);
+
+                return ($primaryClass->isInheritanceTypeJoined())
+                    ? new Exec\MultiTableDeleteExecutor($AST, $this)
+                    : new Exec\SingleTableDeleteUpdateExecutor($AST, $this);
+
+            case ($AST instanceof AST\UpdateStatement):
+                $primaryClass = $this->em->getClassMetadata($AST->updateClause->abstractSchemaName);
+
+                return ($primaryClass->isInheritanceTypeJoined())
+                    ? new Exec\MultiTableUpdateExecutor($AST, $this)
+                    : new Exec\SingleTableDeleteUpdateExecutor($AST, $this);
+
+            default:
+                return new Exec\SingleSelectExecutor($AST, $this);
+        }
+    }
+
+    /**
+     * Generates a unique, short SQL table alias.
+     *
+     * @param string $tableName Table name
+     * @param string $dqlAlias The DQL alias.
+     * @return string Generated table alias.
+     */
+    public function getSQLTableAlias($tableName, $dqlAlias = '')
+    {
+        $tableName .= ($dqlAlias) ? '@[' . $dqlAlias . ']' : '';
+
+        if ( ! isset($this->tableAliasMap[$tableName])) {
+            $this->tableAliasMap[$tableName] = strtolower(substr($tableName, 0, 1)) . $this->tableAliasCounter++ . '_';
+        }
+
+        return $this->tableAliasMap[$tableName];
+    }
+
+    /**
+     * Forces the SqlWalker to use a specific alias for a table name, rather than
+     * generating an alias on its own.
+     *
+     * @param string $tableName
+     * @param string $alias
+     * @param string $dqlAlias
+     * @return string
+     */
+    public function setSQLTableAlias($tableName, $alias, $dqlAlias = '')
+    {
+        $tableName .= ($dqlAlias) ? '@[' . $dqlAlias . ']' : '';
+
+        $this->tableAliasMap[$tableName] = $alias;
+
+        return $alias;
+    }
+
+    /**
+     * Gets an SQL column alias for a column name.
+     *
+     * @param string $columnName
+     * @return string
+     */
+    public function getSQLColumnAlias($columnName)
+    {
+        return $this->quoteStrategy->getColumnAlias($columnName, $this->aliasCounter++, $this->platform);
+    }
+
+    /**
+     * Generates the SQL JOINs that are necessary for Class Table Inheritance
+     * for the given class.
+     *
+     * @param ClassMetadata $class The class for which to generate the joins.
+     * @param string $dqlAlias The DQL alias of the class.
+     * @return string The SQL.
+     */
+    private function _generateClassTableInheritanceJoins($class, $dqlAlias)
+    {
+        $sql = '';
+
+        $baseTableAlias = $this->getSQLTableAlias($class->getTableName(), $dqlAlias);
+
+        // INNER JOIN parent class tables
+        foreach ($class->parentClasses as $parentClassName) {
+            $parentClass = $this->em->getClassMetadata($parentClassName);
+            $tableAlias  = $this->getSQLTableAlias($parentClass->getTableName(), $dqlAlias);
+
+            // If this is a joined association we must use left joins to preserve the correct result.
+            $sql .= isset($this->queryComponents[$dqlAlias]['relation']) ? ' LEFT ' : ' INNER ';
+            $sql .= 'JOIN ' . $this->quoteStrategy->getTableName($parentClass, $this->platform) . ' ' . $tableAlias . ' ON ';
+
+            $sqlParts = array();
+
+            foreach ($this->quoteStrategy->getIdentifierColumnNames($class, $this->platform) as $columnName) {
+                $sqlParts[] = $baseTableAlias . '.' . $columnName . ' = ' . $tableAlias . '.' . $columnName;
+            }
+
+            // Add filters on the root class
+            if ($filterSql = $this->generateFilterConditionSQL($parentClass, $tableAlias)) {
+                $sqlParts[] = $filterSql;
+            }
+
+            $sql .= implode(' AND ', $sqlParts);
+        }
+
+        // Ignore subclassing inclusion if partial objects is disallowed
+        if ($this->query->getHint(Query::HINT_FORCE_PARTIAL_LOAD)) {
+            return $sql;
+        }
+
+        // LEFT JOIN child class tables
+        foreach ($class->subClasses as $subClassName) {
+            $subClass   = $this->em->getClassMetadata($subClassName);
+            $tableAlias = $this->getSQLTableAlias($subClass->getTableName(), $dqlAlias);
+
+            $sql .= ' LEFT JOIN ' . $this->quoteStrategy->getTableName($subClass, $this->platform) . ' ' . $tableAlias . ' ON ';
+
+            $sqlParts = array();
+
+            foreach ($this->quoteStrategy->getIdentifierColumnNames($subClass, $this->platform) as $columnName) {
+                $sqlParts[] = $baseTableAlias . '.' . $columnName . ' = ' . $tableAlias . '.' . $columnName;
+            }
+
+            $sql .= implode(' AND ', $sqlParts);
+        }
+
+        return $sql;
+    }
+
+    private function _generateOrderedCollectionOrderByItems()
+    {
+        $sqlParts = array();
+
+        foreach ($this->selectedClasses as $selectedClass) {
+            $dqlAlias = $selectedClass['dqlAlias'];
+            $qComp    = $this->queryComponents[$dqlAlias];
+
+            if ( ! isset($qComp['relation']['orderBy'])) continue;
+
+            foreach ($qComp['relation']['orderBy'] as $fieldName => $orientation) {
+                $columnName = $this->quoteStrategy->getColumnName($fieldName, $qComp['metadata'], $this->platform);
+                $tableName  = ($qComp['metadata']->isInheritanceTypeJoined())
+                    ? $this->em->getUnitOfWork()->getEntityPersister($qComp['metadata']->name)->getOwningTable($fieldName)
+                    : $qComp['metadata']->getTableName();
+
+                $sqlParts[] = $this->getSQLTableAlias($tableName, $dqlAlias) . '.' . $columnName . ' ' . $orientation;
+            }
+        }
+
+        return implode(', ', $sqlParts);
+    }
+
+    /**
+     * Generates a discriminator column SQL condition for the class with the given DQL alias.
+     *
+     * @param array $dqlAliases List of root DQL aliases to inspect for discriminator restrictions.
+     * @return string
+     */
+    private function _generateDiscriminatorColumnConditionSQL(array $dqlAliases)
+    {
+        $sqlParts = array();
+
+        foreach ($dqlAliases as $dqlAlias) {
+            $class = $this->queryComponents[$dqlAlias]['metadata'];
+
+            if ( ! $class->isInheritanceTypeSingleTable()) continue;
+
+            $conn   = $this->em->getConnection();
+            $values = array();
+
+            if ($class->discriminatorValue !== null) { // discrimnators can be 0
+                $values[] = $conn->quote($class->discriminatorValue);
+            }
+
+            foreach ($class->subClasses as $subclassName) {
+                $values[] = $conn->quote($this->em->getClassMetadata($subclassName)->discriminatorValue);
+            }
+
+            $sqlParts[] = (($this->useSqlTableAliases) ? $this->getSQLTableAlias($class->getTableName(), $dqlAlias) . '.' : '')
+                        . $class->discriminatorColumn['name'] . ' IN (' . implode(', ', $values) . ')';
+        }
+
+        $sql = implode(' AND ', $sqlParts);
+
+        return (count($sqlParts) > 1) ? '(' . $sql . ')' : $sql;
+    }
+
+    /**
+     * Generates the filter SQL for a given entity and table alias.
+     *
+     * @param ClassMetadata $targetEntity Metadata of the target entity.
+     * @param string $targetTableAlias The table alias of the joined/selected table.
+     *
+     * @return string The SQL query part to add to a query.
+     */
+    private function generateFilterConditionSQL(ClassMetadata $targetEntity, $targetTableAlias)
+    {
+        if (!$this->em->hasFilters()) {
+            return '';
+        }
+
+        switch($targetEntity->inheritanceType) {
+            case ClassMetadata::INHERITANCE_TYPE_NONE:
+                break;
+            case ClassMetadata::INHERITANCE_TYPE_JOINED:
+                // The classes in the inheritance will be added to the query one by one,
+                // but only the root node is getting filtered
+                if ($targetEntity->name !== $targetEntity->rootEntityName) {
+                    return '';
+                }
+                break;
+            case ClassMetadata::INHERITANCE_TYPE_SINGLE_TABLE:
+                // With STI the table will only be queried once, make sure that the filters
+                // are added to the root entity
+                $targetEntity = $this->em->getClassMetadata($targetEntity->rootEntityName);
+                break;
+            default:
+                //@todo: throw exception?
+                return '';
+            break;
+        }
+
+        $filterClauses = array();
+        foreach ($this->em->getFilters()->getEnabledFilters() as $filter) {
+            if ('' !== $filterExpr = $filter->addFilterConstraint($targetEntity, $targetTableAlias)) {
+                $filterClauses[] = '(' . $filterExpr . ')';
+            }
+        }
+
+        return implode(' AND ', $filterClauses);
+    }
+    /**
+     * Walks down a SelectStatement AST node, thereby generating the appropriate SQL.
+     *
+     * @return string The SQL.
+     */
+    public function walkSelectStatement(AST\SelectStatement $AST)
+    {
+        $sql  = $this->walkSelectClause($AST->selectClause);
+        $sql .= $this->walkFromClause($AST->fromClause);
+        $sql .= $this->walkWhereClause($AST->whereClause);
+        $sql .= $AST->groupByClause ? $this->walkGroupByClause($AST->groupByClause) : '';
+        $sql .= $AST->havingClause ? $this->walkHavingClause($AST->havingClause) : '';
+
+        if (($orderByClause = $AST->orderByClause) !== null) {
+            $sql .= $AST->orderByClause ? $this->walkOrderByClause($AST->orderByClause) : '';
+        } else if (($orderBySql = $this->_generateOrderedCollectionOrderByItems()) !== '') {
+            $sql .= ' ORDER BY ' . $orderBySql;
+        }
+
+        $sql = $this->platform->modifyLimitQuery(
+            $sql, $this->query->getMaxResults(), $this->query->getFirstResult()
+        );
+
+        if (($lockMode = $this->query->getHint(Query::HINT_LOCK_MODE)) !== false) {
+            switch ($lockMode) {
+                case LockMode::PESSIMISTIC_READ:
+                    $sql .= ' ' . $this->platform->getReadLockSQL();
+                    break;
+
+                case LockMode::PESSIMISTIC_WRITE:
+                    $sql .= ' ' . $this->platform->getWriteLockSQL();
+                    break;
+
+                case LockMode::OPTIMISTIC:
+                    foreach ($this->selectedClasses as $selectedClass) {
+                        if ( ! $selectedClass['class']->isVersioned) {
+                            throw \Doctrine\ORM\OptimisticLockException::lockFailed($selectedClass['class']->name);
+                        }
+                    }
+                    break;
+                case LockMode::NONE:
+                    break;
+
+                default:
+                    throw \Doctrine\ORM\Query\QueryException::invalidLockMode();
+            }
+        }
+
+        return $sql;
+    }
+
+    /**
+     * Walks down an UpdateStatement AST node, thereby generating the appropriate SQL.
+     *
+     * @param UpdateStatement
+     * @return string The SQL.
+     */
+    public function walkUpdateStatement(AST\UpdateStatement $AST)
+    {
+        $this->useSqlTableAliases = false;
+
+        return $this->walkUpdateClause($AST->updateClause)
+             . $this->walkWhereClause($AST->whereClause);
+    }
+
+    /**
+     * Walks down a DeleteStatement AST node, thereby generating the appropriate SQL.
+     *
+     * @param DeleteStatement
+     * @return string The SQL.
+     */
+    public function walkDeleteStatement(AST\DeleteStatement $AST)
+    {
+        $this->useSqlTableAliases = false;
+
+        return $this->walkDeleteClause($AST->deleteClause)
+             . $this->walkWhereClause($AST->whereClause);
+    }
+
+    /**
+     * Walks down an IdentificationVariable AST node, thereby generating the appropriate SQL.
+     * This one differs of ->walkIdentificationVariable() because it generates the entity identifiers.
+     *
+     * @param string $identVariable
+     * @return string
+     */
+    public function walkEntityIdentificationVariable($identVariable)
+    {
+        $class      = $this->queryComponents[$identVariable]['metadata'];
+        $tableAlias = $this->getSQLTableAlias($class->getTableName(), $identVariable);
+        $sqlParts   = array();
+
+        foreach ($this->quoteStrategy->getIdentifierColumnNames($class, $this->platform) as $columnName) {
+            $sqlParts[] = $tableAlias . '.' . $columnName;
+        }
+
+        return implode(', ', $sqlParts);
+    }
+
+    /**
+     * Walks down an IdentificationVariable (no AST node associated), thereby generating the SQL.
+     *
+     * @param string $identificationVariable
+     * @param string $fieldName
+     * @return string The SQL.
+     */
+    public function walkIdentificationVariable($identificationVariable, $fieldName = null)
+    {
+        $class = $this->queryComponents[$identificationVariable]['metadata'];
+
+        if (
+            $fieldName !== null && $class->isInheritanceTypeJoined() &&
+            isset($class->fieldMappings[$fieldName]['inherited'])
+        ) {
+            $class = $this->em->getClassMetadata($class->fieldMappings[$fieldName]['inherited']);
+        }
+
+        return $this->getSQLTableAlias($class->getTableName(), $identificationVariable);
+    }
+
+    /**
+     * Walks down a PathExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param mixed
+     * @return string The SQL.
+     */
+    public function walkPathExpression($pathExpr)
+    {
+        $sql = '';
+
+        switch ($pathExpr->type) {
+            case AST\PathExpression::TYPE_STATE_FIELD:
+                $fieldName = $pathExpr->field;
+                $dqlAlias = $pathExpr->identificationVariable;
+                $class = $this->queryComponents[$dqlAlias]['metadata'];
+
+                if ($this->useSqlTableAliases) {
+                    $sql .= $this->walkIdentificationVariable($dqlAlias, $fieldName) . '.';
+                }
+
+                $sql .= $this->quoteStrategy->getColumnName($fieldName, $class, $this->platform);
+                break;
+
+            case AST\PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION:
+                // 1- the owning side:
+                //    Just use the foreign key, i.e. u.group_id
+                $fieldName = $pathExpr->field;
+                $dqlAlias = $pathExpr->identificationVariable;
+                $class = $this->queryComponents[$dqlAlias]['metadata'];
+
+                if (isset($class->associationMappings[$fieldName]['inherited'])) {
+                    $class = $this->em->getClassMetadata($class->associationMappings[$fieldName]['inherited']);
+                }
+
+                $assoc = $class->associationMappings[$fieldName];
+
+                if ( ! $assoc['isOwningSide']) {
+                    throw QueryException::associationPathInverseSideNotSupported();
+                }
+
+                // COMPOSITE KEYS NOT (YET?) SUPPORTED
+                if (count($assoc['sourceToTargetKeyColumns']) > 1) {
+                    throw QueryException::associationPathCompositeKeyNotSupported();
+                }
+
+                if ($this->useSqlTableAliases) {
+                    $sql .= $this->getSQLTableAlias($class->getTableName(), $dqlAlias) . '.';
+                }
+
+                $sql .= reset($assoc['targetToSourceKeyColumns']);
+                break;
+
+            default:
+                throw QueryException::invalidPathExpression($pathExpr);
+        }
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a SelectClause AST node, thereby generating the appropriate SQL.
+     *
+     * @param $selectClause
+     * @return string The SQL.
+     */
+    public function walkSelectClause($selectClause)
+    {
+        $sql = 'SELECT ' . (($selectClause->isDistinct) ? 'DISTINCT ' : '');
+        $sqlSelectExpressions = array_filter(array_map(array($this, 'walkSelectExpression'), $selectClause->selectExpressions));
+
+        if ($this->query->getHint(Query::HINT_INTERNAL_ITERATION) == true && $selectClause->isDistinct) {
+            $this->query->setHint(self::HINT_DISTINCT, true);
+        }
+
+        $addMetaColumns = ! $this->query->getHint(Query::HINT_FORCE_PARTIAL_LOAD) &&
+                $this->query->getHydrationMode() == Query::HYDRATE_OBJECT
+                ||
+                $this->query->getHydrationMode() != Query::HYDRATE_OBJECT &&
+                $this->query->getHint(Query::HINT_INCLUDE_META_COLUMNS);
+
+        foreach ($this->selectedClasses as $selectedClass) {
+            $class       = $selectedClass['class'];
+            $dqlAlias    = $selectedClass['dqlAlias'];
+            $resultAlias = $selectedClass['resultAlias'];
+
+            // Register as entity or joined entity result
+            if ($this->queryComponents[$dqlAlias]['relation'] === null) {
+                $this->rsm->addEntityResult($class->name, $dqlAlias, $resultAlias);
+            } else {
+                $this->rsm->addJoinedEntityResult(
+                    $class->name,
+                    $dqlAlias,
+                    $this->queryComponents[$dqlAlias]['parent'],
+                    $this->queryComponents[$dqlAlias]['relation']['fieldName']
+                );
+            }
+
+            if ($class->isInheritanceTypeSingleTable() || $class->isInheritanceTypeJoined()) {
+                // Add discriminator columns to SQL
+                $rootClass   = $this->em->getClassMetadata($class->rootEntityName);
+                $tblAlias    = $this->getSQLTableAlias($rootClass->getTableName(), $dqlAlias);
+                $discrColumn = $rootClass->discriminatorColumn;
+                $columnAlias = $this->getSQLColumnAlias($discrColumn['name']);
+
+                $sqlSelectExpressions[] = $tblAlias . '.' . $discrColumn['name'] . ' AS ' . $columnAlias;
+
+                $this->rsm->setDiscriminatorColumn($dqlAlias, $columnAlias);
+                $this->rsm->addMetaResult($dqlAlias, $columnAlias, $discrColumn['fieldName']);
+            }
+
+            // Add foreign key columns to SQL, if necessary
+            if ( ! $addMetaColumns && ! $class->containsForeignIdentifier) {
+                continue;
+            }
+
+            // Add foreign key columns of class and also parent classes
+            foreach ($class->associationMappings as $assoc) {
+                if ( ! ($assoc['isOwningSide'] && $assoc['type'] & ClassMetadata::TO_ONE)) {
+                    continue;
+                } else if ( !$addMetaColumns && !isset($assoc['id'])) {
+                    continue;
+                }
+
+                $owningClass   = (isset($assoc['inherited'])) ? $this->em->getClassMetadata($assoc['inherited']) : $class;
+                $sqlTableAlias = $this->getSQLTableAlias($owningClass->getTableName(), $dqlAlias);
+
+                foreach ($assoc['targetToSourceKeyColumns'] as $srcColumn) {
+                    $columnAlias = $this->getSQLColumnAlias($srcColumn);
+
+                    $sqlSelectExpressions[] = $sqlTableAlias . '.' . $srcColumn . ' AS ' . $columnAlias;
+
+                    $this->rsm->addMetaResult($dqlAlias, $columnAlias, $srcColumn, (isset($assoc['id']) && $assoc['id'] === true));
+                }
+            }
+
+            // Add foreign key columns to SQL, if necessary
+            if ( ! $addMetaColumns) {
+                continue;
+            }
+
+            // Add foreign key columns of subclasses
+            foreach ($class->subClasses as $subClassName) {
+                $subClass      = $this->em->getClassMetadata($subClassName);
+                $sqlTableAlias = $this->getSQLTableAlias($subClass->getTableName(), $dqlAlias);
+
+                foreach ($subClass->associationMappings as $assoc) {
+                    // Skip if association is inherited
+                    if (isset($assoc['inherited'])) continue;
+
+                    if ( ! ($assoc['isOwningSide'] && $assoc['type'] & ClassMetadata::TO_ONE)) continue;
+
+                    foreach ($assoc['targetToSourceKeyColumns'] as $srcColumn) {
+                        $columnAlias = $this->getSQLColumnAlias($srcColumn);
+
+                        $sqlSelectExpressions[] = $sqlTableAlias . '.' . $srcColumn . ' AS ' . $columnAlias;
+
+                        $this->rsm->addMetaResult($dqlAlias, $columnAlias, $srcColumn);
+                    }
+                }
+            }
+        }
+
+        $sql .= implode(', ', $sqlSelectExpressions);
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a FromClause AST node, thereby generating the appropriate SQL.
+     *
+     * @return string The SQL.
+     */
+    public function walkFromClause($fromClause)
+    {
+        $identificationVarDecls = $fromClause->identificationVariableDeclarations;
+        $sqlParts = array();
+
+        foreach ($identificationVarDecls as $identificationVariableDecl) {
+            $sql = $this->walkRangeVariableDeclaration($identificationVariableDecl->rangeVariableDeclaration);
+
+            foreach ($identificationVariableDecl->joins as $join) {
+                $sql .= $this->walkJoin($join);
+            }
+
+            if ($identificationVariableDecl->indexBy) {
+                $alias = $identificationVariableDecl->indexBy->simpleStateFieldPathExpression->identificationVariable;
+                $field = $identificationVariableDecl->indexBy->simpleStateFieldPathExpression->field;
+
+                if (isset($this->scalarFields[$alias][$field])) {
+                    $this->rsm->addIndexByScalar($this->scalarFields[$alias][$field]);
+                } else {
+                    $this->rsm->addIndexBy(
+                        $identificationVariableDecl->indexBy->simpleStateFieldPathExpression->identificationVariable,
+                        $identificationVariableDecl->indexBy->simpleStateFieldPathExpression->field
+                    );
+                }
+            }
+
+            $sqlParts[] = $this->platform->appendLockHint($sql, $this->query->getHint(Query::HINT_LOCK_MODE));
+        }
+
+        return ' FROM ' . implode(', ', $sqlParts);
+    }
+
+    /**
+     * Walks down a RangeVariableDeclaration AST node, thereby generating the appropriate SQL.
+     *
+     * @return string
+     */
+    public function walkRangeVariableDeclaration($rangeVariableDeclaration)
+    {
+        $class    = $this->em->getClassMetadata($rangeVariableDeclaration->abstractSchemaName);
+        $dqlAlias = $rangeVariableDeclaration->aliasIdentificationVariable;
+
+        $this->rootAliases[] = $dqlAlias;
+
+        $sql = $class->getQuotedTableName($this->platform) . ' '
+             . $this->getSQLTableAlias($class->getTableName(), $dqlAlias);
+
+        if ($class->isInheritanceTypeJoined()) {
+            $sql .= $this->_generateClassTableInheritanceJoins($class, $dqlAlias);
+        }
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a JoinAssociationDeclaration AST node, thereby generating the appropriate SQL.
+     *
+     * @return string
+     */
+    public function walkJoinAssociationDeclaration($joinAssociationDeclaration, $joinType = AST\Join::JOIN_TYPE_INNER)
+    {
+        $sql = '';
+
+        $associationPathExpression = $joinAssociationDeclaration->joinAssociationPathExpression;
+        $joinedDqlAlias            = $joinAssociationDeclaration->aliasIdentificationVariable;
+        $indexBy                   = $joinAssociationDeclaration->indexBy;
+
+        $relation        = $this->queryComponents[$joinedDqlAlias]['relation'];
+        $targetClass     = $this->em->getClassMetadata($relation['targetEntity']);
+        $sourceClass     = $this->em->getClassMetadata($relation['sourceEntity']);
+        $targetTableName = $targetClass->getQuotedTableName($this->platform);
+
+        $targetTableAlias = $this->getSQLTableAlias($targetClass->getTableName(), $joinedDqlAlias);
+        $sourceTableAlias = $this->getSQLTableAlias($sourceClass->getTableName(), $associationPathExpression->identificationVariable);
+
+        // Ensure we got the owning side, since it has all mapping info
+        $assoc = ( ! $relation['isOwningSide']) ? $targetClass->associationMappings[$relation['mappedBy']] : $relation;
+
+        if ($this->query->getHint(Query::HINT_INTERNAL_ITERATION) == true && (!$this->query->getHint(self::HINT_DISTINCT) || isset($this->selectedClasses[$joinedDqlAlias]))) {
+            if ($relation['type'] == ClassMetadata::ONE_TO_MANY || $relation['type'] == ClassMetadata::MANY_TO_MANY) {
+                throw QueryException::iterateWithFetchJoinNotAllowed($assoc);
+            }
+        }
+
+        // This condition is not checking ClassMetadata::MANY_TO_ONE, because by definition it cannot
+        // be the owning side and previously we ensured that $assoc is always the owning side of the associations.
+        // The owning side is necessary at this point because only it contains the JoinColumn information.
+        switch (true) {
+            case ($assoc['type'] & ClassMetadata::TO_ONE):
+                $conditions = array();
+
+                 foreach ($assoc['joinColumns'] as $joinColumn) {
+                    $quotedSourceColumn = $this->quoteStrategy->getJoinColumnName($joinColumn, $targetClass, $this->platform);
+                    $quotedTargetColumn = $this->quoteStrategy->getReferencedJoinColumnName($joinColumn, $targetClass, $this->platform);
+
+                    if ($relation['isOwningSide']) {
+                        $conditions[] = $sourceTableAlias . '.' . $quotedSourceColumn . ' = ' . $targetTableAlias . '.' . $quotedTargetColumn;
+
+                        continue;
+                    }
+
+                    $conditions[] = $sourceTableAlias . '.' . $quotedTargetColumn . ' = ' . $targetTableAlias . '.' . $quotedSourceColumn;
+                }
+
+                // Apply remaining inheritance restrictions
+                $discrSql = $this->_generateDiscriminatorColumnConditionSQL(array($joinedDqlAlias));
+
+                if ($discrSql) {
+                    $conditions[] = $discrSql;
+                }
+
+                // Apply the filters
+                $filterExpr = $this->generateFilterConditionSQL($targetClass, $targetTableAlias);
+
+                if ($filterExpr) {
+                    $conditions[] = $filterExpr;
+                }
+
+                $sql .= $targetTableName . ' ' . $targetTableAlias . ' ON ' . implode(' AND ', $conditions);
+                break;
+
+            case ($assoc['type'] == ClassMetadata::MANY_TO_MANY):
+                // Join relation table
+                $joinTable      = $assoc['joinTable'];
+                $joinTableAlias = $this->getSQLTableAlias($joinTable['name'], $joinedDqlAlias);
+                $joinTableName  = $sourceClass->getQuotedJoinTableName($assoc, $this->platform);
+
+                $conditions      = array();
+                $relationColumns = ($relation['isOwningSide'])
+                    ? $assoc['joinTable']['joinColumns']
+                    : $assoc['joinTable']['inverseJoinColumns'];
+
+                foreach ($relationColumns as $joinColumn) {
+                    $quotedSourceColumn = $this->quoteStrategy->getJoinColumnName($joinColumn, $targetClass, $this->platform);
+                    $quotedTargetColumn = $this->quoteStrategy->getReferencedJoinColumnName($joinColumn, $targetClass, $this->platform);
+
+                    $conditions[] = $sourceTableAlias . '.' . $quotedTargetColumn . ' = ' . $joinTableAlias . '.' . $quotedSourceColumn;
+                }
+
+                $sql .= $joinTableName . ' ' . $joinTableAlias . ' ON ' . implode(' AND ', $conditions);
+
+                // Join target table
+                $sql .= ($joinType == AST\Join::JOIN_TYPE_LEFT || $joinType == AST\Join::JOIN_TYPE_LEFTOUTER) ? ' LEFT JOIN ' : ' INNER JOIN ';
+
+                $conditions      = array();
+                $relationColumns = ($relation['isOwningSide'])
+                    ? $assoc['joinTable']['inverseJoinColumns']
+                    : $assoc['joinTable']['joinColumns'];
+
+                foreach ($relationColumns as $joinColumn) {
+                    $quotedSourceColumn = $this->quoteStrategy->getJoinColumnName($joinColumn, $targetClass, $this->platform);
+                    $quotedTargetColumn = $this->quoteStrategy->getReferencedJoinColumnName($joinColumn, $targetClass, $this->platform);
+
+                    $conditions[] = $targetTableAlias . '.' . $quotedTargetColumn . ' = ' . $joinTableAlias . '.' . $quotedSourceColumn;
+                }
+
+                // Apply remaining inheritance restrictions
+                $discrSql = $this->_generateDiscriminatorColumnConditionSQL(array($joinedDqlAlias));
+
+                if ($discrSql) {
+                    $conditions[] = $discrSql;
+                }
+
+                // Apply the filters
+                $filterExpr = $this->generateFilterConditionSQL($targetClass, $targetTableAlias);
+
+                if ($filterExpr) {
+                    $conditions[] = $filterExpr;
+                }
+
+                $sql .= $targetTableName . ' ' . $targetTableAlias . ' ON ' . implode(' AND ', $conditions);
+                break;
+        }
+
+        // FIXME: these should either be nested or all forced to be left joins (DDC-XXX)
+        if ($targetClass->isInheritanceTypeJoined()) {
+            $sql .= $this->_generateClassTableInheritanceJoins($targetClass, $joinedDqlAlias);
+        }
+
+        // Apply the indexes
+        if ($indexBy) {
+            // For Many-To-One or One-To-One associations this obviously makes no sense, but is ignored silently.
+            $this->rsm->addIndexBy(
+                $indexBy->simpleStateFieldPathExpression->identificationVariable,
+                $indexBy->simpleStateFieldPathExpression->field
+            );
+        } else if (isset($relation['indexBy'])) {
+            $this->rsm->addIndexBy($joinedDqlAlias, $relation['indexBy']);
+        }
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a FunctionNode AST node, thereby generating the appropriate SQL.
+     *
+     * @return string The SQL.
+     */
+    public function walkFunction($function)
+    {
+        return $function->getSql($this);
+    }
+
+    /**
+     * Walks down an OrderByClause AST node, thereby generating the appropriate SQL.
+     *
+     * @param OrderByClause
+     * @return string The SQL.
+     */
+    public function walkOrderByClause($orderByClause)
+    {
+        $orderByItems = array_map(array($this, 'walkOrderByItem'), $orderByClause->orderByItems);
+
+        if (($collectionOrderByItems = $this->_generateOrderedCollectionOrderByItems()) !== '') {
+            $orderByItems = array_merge($orderByItems, (array) $collectionOrderByItems);
+        }
+
+        return ' ORDER BY ' . implode(', ', $orderByItems);
+    }
+
+    /**
+     * Walks down an OrderByItem AST node, thereby generating the appropriate SQL.
+     *
+     * @param OrderByItem
+     * @return string The SQL.
+     */
+    public function walkOrderByItem($orderByItem)
+    {
+        $expr = $orderByItem->expression;
+        $sql  = ($expr instanceof AST\Node)
+            ? $expr->dispatch($this)
+            : $this->walkResultVariable($this->queryComponents[$expr]['token']['value']);
+
+        return $sql . ' ' . strtoupper($orderByItem->type);
+    }
+
+    /**
+     * Walks down a HavingClause AST node, thereby generating the appropriate SQL.
+     *
+     * @param HavingClause
+     * @return string The SQL.
+     */
+    public function walkHavingClause($havingClause)
+    {
+        return ' HAVING ' . $this->walkConditionalExpression($havingClause->conditionalExpression);
+    }
+
+    /**
+     * Walks down a Join AST node and creates the corresponding SQL.
+     *
+     * @return string The SQL.
+     */
+    public function walkJoin($join)
+    {
+        $joinType        = $join->joinType;
+        $joinDeclaration = $join->joinAssociationDeclaration;
+
+        $sql = ($joinType == AST\Join::JOIN_TYPE_LEFT || $joinType == AST\Join::JOIN_TYPE_LEFTOUTER)
+            ? ' LEFT JOIN '
+            : ' INNER JOIN ';
+
+        switch (true) {
+            case ($joinDeclaration instanceof \Doctrine\ORM\Query\AST\RangeVariableDeclaration):
+                $sql .= $this->walkRangeVariableDeclaration($joinDeclaration)
+                      . ' ON (' . $this->walkConditionalExpression($join->conditionalExpression) . ')';
+                break;
+
+            case ($joinDeclaration instanceof \Doctrine\ORM\Query\AST\JoinAssociationDeclaration):
+                $sql .= $this->walkJoinAssociationDeclaration($joinDeclaration, $joinType);
+
+                // Handle WITH clause
+                if (($condExpr = $join->conditionalExpression) !== null) {
+                    // Phase 2 AST optimization: Skip processment of ConditionalExpression
+                    // if only one ConditionalTerm is defined
+                    $sql .= ' AND (' . $this->walkConditionalExpression($condExpr) . ')';
+                }
+                break;
+        }
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a CaseExpression AST node and generates the corresponding SQL.
+     *
+     * @param CoalesceExpression|NullIfExpression|GeneralCaseExpression|SimpleCaseExpression $expression
+     * @return string The SQL.
+     */
+    public function walkCaseExpression($expression)
+    {
+        switch (true) {
+            case ($expression instanceof AST\CoalesceExpression):
+                return $this->walkCoalesceExpression($expression);
+
+            case ($expression instanceof AST\NullIfExpression):
+                return $this->walkNullIfExpression($expression);
+
+            case ($expression instanceof AST\GeneralCaseExpression):
+                return $this->walkGeneralCaseExpression($expression);
+
+            case ($expression instanceof AST\SimpleCaseExpression):
+                return $this->walkSimpleCaseExpression($expression);
+
+            default:
+                return '';
+        }
+    }
+
+    /**
+     * Walks down a CoalesceExpression AST node and generates the corresponding SQL.
+     *
+     * @param CoalesceExpression $coalesceExpression
+     * @return string The SQL.
+     */
+    public function walkCoalesceExpression($coalesceExpression)
+    {
+        $sql = 'COALESCE(';
+
+        $scalarExpressions = array();
+
+        foreach ($coalesceExpression->scalarExpressions as $scalarExpression) {
+            $scalarExpressions[] = $this->walkSimpleArithmeticExpression($scalarExpression);
+        }
+
+        $sql .= implode(', ', $scalarExpressions) . ')';
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a NullIfExpression AST node and generates the corresponding SQL.
+     *
+     * @param NullIfExpression $nullIfExpression
+     * @return string The SQL.
+     */
+    public function walkNullIfExpression($nullIfExpression)
+    {
+        $firstExpression = is_string($nullIfExpression->firstExpression)
+            ? $this->conn->quote($nullIfExpression->firstExpression)
+            : $this->walkSimpleArithmeticExpression($nullIfExpression->firstExpression);
+
+        $secondExpression = is_string($nullIfExpression->secondExpression)
+            ? $this->conn->quote($nullIfExpression->secondExpression)
+            : $this->walkSimpleArithmeticExpression($nullIfExpression->secondExpression);
+
+        return 'NULLIF(' . $firstExpression . ', ' . $secondExpression . ')';
+    }
+
+    /**
+     * Walks down a GeneralCaseExpression AST node and generates the corresponding SQL.
+     *
+     * @param GeneralCaseExpression $generalCaseExpression
+     * @return string The SQL.
+     */
+    public function walkGeneralCaseExpression(AST\GeneralCaseExpression $generalCaseExpression)
+    {
+        $sql = 'CASE';
+
+        foreach ($generalCaseExpression->whenClauses as $whenClause) {
+            $sql .= ' WHEN ' . $this->walkConditionalExpression($whenClause->caseConditionExpression);
+            $sql .= ' THEN ' . $this->walkSimpleArithmeticExpression($whenClause->thenScalarExpression);
+        }
+
+        $sql .= ' ELSE ' . $this->walkSimpleArithmeticExpression($generalCaseExpression->elseScalarExpression) . ' END';
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a SimpleCaseExpression AST node and generates the corresponding SQL.
+     *
+     * @param SimpleCaseExpression $simpleCaseExpression
+     * @return string The SQL.
+     */
+    public function walkSimpleCaseExpression($simpleCaseExpression)
+    {
+        $sql = 'CASE ' . $this->walkStateFieldPathExpression($simpleCaseExpression->caseOperand);
+
+        foreach ($simpleCaseExpression->simpleWhenClauses as $simpleWhenClause) {
+            $sql .= ' WHEN ' . $this->walkSimpleArithmeticExpression($simpleWhenClause->caseScalarExpression);
+            $sql .= ' THEN ' . $this->walkSimpleArithmeticExpression($simpleWhenClause->thenScalarExpression);
+        }
+
+        $sql .= ' ELSE ' . $this->walkSimpleArithmeticExpression($simpleCaseExpression->elseScalarExpression) . ' END';
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a SelectExpression AST node and generates the corresponding SQL.
+     *
+     * @param SelectExpression $selectExpression
+     * @return string The SQL.
+     */
+    public function walkSelectExpression($selectExpression)
+    {
+        $sql    = '';
+        $expr   = $selectExpression->expression;
+        $hidden = $selectExpression->hiddenAliasResultVariable;
+
+        switch (true) {
+            case ($expr instanceof AST\PathExpression):
+                if ($expr->type !== AST\PathExpression::TYPE_STATE_FIELD) {
+                    throw QueryException::invalidPathExpression($expr->type);
+                }
+
+                $fieldName = $expr->field;
+                $dqlAlias  = $expr->identificationVariable;
+                $qComp     = $this->queryComponents[$dqlAlias];
+                $class     = $qComp['metadata'];
+
+                $resultAlias = $selectExpression->fieldIdentificationVariable ?: $fieldName;
+                $tableName   = ($class->isInheritanceTypeJoined())
+                    ? $this->em->getUnitOfWork()->getEntityPersister($class->name)->getOwningTable($fieldName)
+                    : $class->getTableName();
+
+                $sqlTableAlias = $this->getSQLTableAlias($tableName, $dqlAlias);
+                $columnName    = $this->quoteStrategy->getColumnName($fieldName, $class, $this->platform);
+                $columnAlias   = $this->getSQLColumnAlias($class->fieldMappings[$fieldName]['columnName']);
+
+                $col = $sqlTableAlias . '.' . $columnName;
+
+                $fieldType = $class->getTypeOfField($fieldName);
+
+                if (isset($class->fieldMappings[$fieldName]['requireSQLConversion'])) {
+                    $type = Type::getType($fieldType);
+                    $col  = $type->convertToPHPValueSQL($col, $this->conn->getDatabasePlatform());
+                }
+
+                $sql .= $col . ' AS ' . $columnAlias;
+
+                $this->scalarResultAliasMap[$resultAlias] = $columnAlias;
+
+                if ( ! $hidden) {
+                    $this->rsm->addScalarResult($columnAlias, $resultAlias, $fieldType);
+                    $this->scalarFields[$dqlAlias][$fieldName] = $columnAlias;
+                }
+                break;
+
+            case ($expr instanceof AST\AggregateExpression):
+            case ($expr instanceof AST\Functions\FunctionNode):
+            case ($expr instanceof AST\SimpleArithmeticExpression):
+            case ($expr instanceof AST\ArithmeticTerm):
+            case ($expr instanceof AST\ArithmeticFactor):
+            case ($expr instanceof AST\ArithmeticPrimary):
+            case ($expr instanceof AST\Literal):
+            case ($expr instanceof AST\NullIfExpression):
+            case ($expr instanceof AST\CoalesceExpression):
+            case ($expr instanceof AST\GeneralCaseExpression):
+            case ($expr instanceof AST\SimpleCaseExpression):
+                $columnAlias = $this->getSQLColumnAlias('sclr');
+                $resultAlias = $selectExpression->fieldIdentificationVariable ?: $this->scalarResultCounter++;
+
+                $sql .= $expr->dispatch($this) . ' AS ' . $columnAlias;
+
+                $this->scalarResultAliasMap[$resultAlias] = $columnAlias;
+
+                if ( ! $hidden) {
+                    // We cannot resolve field type here; assume 'string'.
+                    $this->rsm->addScalarResult($columnAlias, $resultAlias, 'string');
+                }
+                break;
+
+            case ($expr instanceof AST\Subselect):
+                $columnAlias = $this->getSQLColumnAlias('sclr');
+                $resultAlias = $selectExpression->fieldIdentificationVariable ?: $this->scalarResultCounter++;
+
+                $sql .= '(' . $this->walkSubselect($expr) . ') AS ' . $columnAlias;
+
+                $this->scalarResultAliasMap[$resultAlias] = $columnAlias;
+
+                if ( ! $hidden) {
+                    // We cannot resolve field type here; assume 'string'.
+                    $this->rsm->addScalarResult($columnAlias, $resultAlias, 'string');
+                }
+                break;
+
+            default:
+                // IdentificationVariable or PartialObjectExpression
+                if ($expr instanceof AST\PartialObjectExpression) {
+                    $dqlAlias = $expr->identificationVariable;
+                    $partialFieldSet = $expr->partialFieldSet;
+                } else {
+                    $dqlAlias = $expr;
+                    $partialFieldSet = array();
+                }
+
+                $queryComp   = $this->queryComponents[$dqlAlias];
+                $class       = $queryComp['metadata'];
+                $resultAlias = $selectExpression->fieldIdentificationVariable ?: null;
+
+                if ( ! isset($this->selectedClasses[$dqlAlias])) {
+                    $this->selectedClasses[$dqlAlias] = array(
+                        'class'       => $class,
+                        'dqlAlias'    => $dqlAlias,
+                        'resultAlias' => $resultAlias
+                    );
+                }
+
+                $sqlParts = array();
+
+                // Select all fields from the queried class
+                foreach ($class->fieldMappings as $fieldName => $mapping) {
+                    if ($partialFieldSet && ! in_array($fieldName, $partialFieldSet)) {
+                        continue;
+                    }
+
+                    $tableName = (isset($mapping['inherited']))
+                        ? $this->em->getClassMetadata($mapping['inherited'])->getTableName()
+                        : $class->getTableName();
+
+                    $sqlTableAlias    = $this->getSQLTableAlias($tableName, $dqlAlias);
+                    $columnAlias      = $this->getSQLColumnAlias($mapping['columnName']);
+                    $quotedColumnName = $this->quoteStrategy->getColumnName($fieldName, $class, $this->platform);
+
+                    $col = $sqlTableAlias . '.' . $quotedColumnName;
+
+                    if (isset($class->fieldMappings[$fieldName]['requireSQLConversion'])) {
+                        $type = Type::getType($class->getTypeOfField($fieldName));
+                        $col = $type->convertToPHPValueSQL($col, $this->platform);
+                    }
+
+                    $sqlParts[] = $col . ' AS '. $columnAlias;
+
+                    $this->scalarResultAliasMap[$resultAlias][] = $columnAlias;
+
+                    $this->rsm->addFieldResult($dqlAlias, $columnAlias, $fieldName, $class->name);
+                }
+
+                // Add any additional fields of subclasses (excluding inherited fields)
+                // 1) on Single Table Inheritance: always, since its marginal overhead
+                // 2) on Class Table Inheritance only if partial objects are disallowed,
+                //    since it requires outer joining subtables.
+                if ($class->isInheritanceTypeSingleTable() || ! $this->query->getHint(Query::HINT_FORCE_PARTIAL_LOAD)) {
+                    foreach ($class->subClasses as $subClassName) {
+                        $subClass      = $this->em->getClassMetadata($subClassName);
+                        $sqlTableAlias = $this->getSQLTableAlias($subClass->getTableName(), $dqlAlias);
+
+                        foreach ($subClass->fieldMappings as $fieldName => $mapping) {
+                            if (isset($mapping['inherited']) || $partialFieldSet && !in_array($fieldName, $partialFieldSet)) {
+                                continue;
+                            }
+
+                            $columnAlias      = $this->getSQLColumnAlias($mapping['columnName']);
+                            $quotedColumnName = $this->quoteStrategy->getColumnName($fieldName, $subClass, $this->platform);
+
+                            $col = $sqlTableAlias . '.' . $quotedColumnName;
+
+                            if (isset($subClass->fieldMappings[$fieldName]['requireSQLConversion'])) {
+                                $type = Type::getType($subClass->getTypeOfField($fieldName));
+                                $col = $type->convertToPHPValueSQL($col, $this->platform);
+                            }
+
+                            $sqlParts[] = $col . ' AS ' . $columnAlias;
+
+                            $this->scalarResultAliasMap[$resultAlias][] = $columnAlias;
+
+                            $this->rsm->addFieldResult($dqlAlias, $columnAlias, $fieldName, $subClassName);
+                        }
+                    }
+                }
+
+                $sql .= implode(', ', $sqlParts);
+        }
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a QuantifiedExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param QuantifiedExpression
+     * @return string The SQL.
+     */
+    public function walkQuantifiedExpression($qExpr)
+    {
+        return ' ' . strtoupper($qExpr->type) . '(' . $this->walkSubselect($qExpr->subselect) . ')';
+    }
+
+    /**
+     * Walks down a Subselect AST node, thereby generating the appropriate SQL.
+     *
+     * @param Subselect
+     * @return string The SQL.
+     */
+    public function walkSubselect($subselect)
+    {
+        $useAliasesBefore  = $this->useSqlTableAliases;
+        $rootAliasesBefore = $this->rootAliases;
+
+        $this->rootAliases = array(); // reset the rootAliases for the subselect
+        $this->useSqlTableAliases = true;
+
+        $sql  = $this->walkSimpleSelectClause($subselect->simpleSelectClause);
+        $sql .= $this->walkSubselectFromClause($subselect->subselectFromClause);
+        $sql .= $this->walkWhereClause($subselect->whereClause);
+
+        $sql .= $subselect->groupByClause ? $this->walkGroupByClause($subselect->groupByClause) : '';
+        $sql .= $subselect->havingClause ? $this->walkHavingClause($subselect->havingClause) : '';
+        $sql .= $subselect->orderByClause ? $this->walkOrderByClause($subselect->orderByClause) : '';
+
+        $this->rootAliases        = $rootAliasesBefore; // put the main aliases back
+        $this->useSqlTableAliases = $useAliasesBefore;
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a SubselectFromClause AST node, thereby generating the appropriate SQL.
+     *
+     * @param SubselectFromClause
+     * @return string The SQL.
+     */
+    public function walkSubselectFromClause($subselectFromClause)
+    {
+        $identificationVarDecls = $subselectFromClause->identificationVariableDeclarations;
+        $sqlParts = array ();
+
+        foreach ($identificationVarDecls as $subselectIdVarDecl) {
+            $sql = $this->walkRangeVariableDeclaration($subselectIdVarDecl->rangeVariableDeclaration);
+
+            foreach ($subselectIdVarDecl->joins as $join) {
+                $sql .= $this->walkJoin($join);
+            }
+
+            $sqlParts[] = $this->platform->appendLockHint($sql, $this->query->getHint(Query::HINT_LOCK_MODE));
+        }
+
+        return ' FROM ' . implode(', ', $sqlParts);
+    }
+
+    /**
+     * Walks down a SimpleSelectClause AST node, thereby generating the appropriate SQL.
+     *
+     * @param SimpleSelectClause
+     * @return string The SQL.
+     */
+    public function walkSimpleSelectClause($simpleSelectClause)
+    {
+        return 'SELECT' . ($simpleSelectClause->isDistinct ? ' DISTINCT' : '')
+             . $this->walkSimpleSelectExpression($simpleSelectClause->simpleSelectExpression);
+    }
+
+    /**
+     * Walks down a SimpleSelectExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param SimpleSelectExpression
+     * @return string The SQL.
+     */
+    public function walkSimpleSelectExpression($simpleSelectExpression)
+    {
+        $expr = $simpleSelectExpression->expression;
+        $sql  = ' ';
+
+        switch (true) {
+            case ($expr instanceof AST\PathExpression):
+                $sql .= $this->walkPathExpression($expr);
+                break;
+
+            case ($expr instanceof AST\AggregateExpression):
+                $alias = $simpleSelectExpression->fieldIdentificationVariable ?: $this->scalarResultCounter++;
+
+                $sql .= $this->walkAggregateExpression($expr) . ' AS dctrn__' . $alias;
+                break;
+
+            case ($expr instanceof AST\Subselect):
+                $alias = $simpleSelectExpression->fieldIdentificationVariable ?: $this->scalarResultCounter++;
+
+                $columnAlias = 'sclr' . $this->aliasCounter++;
+                $this->scalarResultAliasMap[$alias] = $columnAlias;
+
+                $sql .= '(' . $this->walkSubselect($expr) . ') AS ' . $columnAlias;
+                break;
+
+            case ($expr instanceof AST\Functions\FunctionNode):
+            case ($expr instanceof AST\SimpleArithmeticExpression):
+            case ($expr instanceof AST\ArithmeticTerm):
+            case ($expr instanceof AST\ArithmeticFactor):
+            case ($expr instanceof AST\ArithmeticPrimary):
+            case ($expr instanceof AST\Literal):
+            case ($expr instanceof AST\NullIfExpression):
+            case ($expr instanceof AST\CoalesceExpression):
+            case ($expr instanceof AST\GeneralCaseExpression):
+            case ($expr instanceof AST\SimpleCaseExpression):
+                $alias = $simpleSelectExpression->fieldIdentificationVariable ?: $this->scalarResultCounter++;
+
+                $columnAlias = $this->getSQLColumnAlias('sclr');
+                $this->scalarResultAliasMap[$alias] = $columnAlias;
+
+                $sql .= $expr->dispatch($this) . ' AS ' . $columnAlias;
+                break;
+
+            default: // IdentificationVariable
+                $sql .= $this->walkEntityIdentificationVariable($expr);
+                break;
+        }
+
+        return $sql;
+    }
+
+    /**
+     * Walks down an AggregateExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param AggregateExpression
+     * @return string The SQL.
+     */
+    public function walkAggregateExpression($aggExpression)
+    {
+        return $aggExpression->functionName . '(' . ($aggExpression->isDistinct ? 'DISTINCT ' : '')
+             . $this->walkSimpleArithmeticExpression($aggExpression->pathExpression) . ')';
+    }
+
+    /**
+     * Walks down a GroupByClause AST node, thereby generating the appropriate SQL.
+     *
+     * @param GroupByClause
+     * @return string The SQL.
+     */
+    public function walkGroupByClause($groupByClause)
+    {
+        $sqlParts = array();
+
+        foreach ($groupByClause->groupByItems as $groupByItem) {
+            $sqlParts[] = $this->walkGroupByItem($groupByItem);
+        }
+
+        return ' GROUP BY ' . implode(', ', $sqlParts);
+    }
+
+    /**
+     * Walks down a GroupByItem AST node, thereby generating the appropriate SQL.
+     *
+     * @param GroupByItem
+     * @return string The SQL.
+     */
+    public function walkGroupByItem($groupByItem)
+    {
+        // StateFieldPathExpression
+        if ( ! is_string($groupByItem)) {
+            return $this->walkPathExpression($groupByItem);
+        }
+
+        // ResultVariable
+        if (isset($this->queryComponents[$groupByItem]['resultVariable'])) {
+            return $this->walkResultVariable($groupByItem);
+        }
+
+        // IdentificationVariable
+        $sqlParts = array();
+
+        foreach ($this->queryComponents[$groupByItem]['metadata']->fieldNames as $field) {
+            $item       = new AST\PathExpression(AST\PathExpression::TYPE_STATE_FIELD, $groupByItem, $field);
+            $item->type = AST\PathExpression::TYPE_STATE_FIELD;
+
+            $sqlParts[] = $this->walkPathExpression($item);
+        }
+
+        foreach ($this->queryComponents[$groupByItem]['metadata']->associationMappings as $mapping) {
+            if ($mapping['isOwningSide'] && $mapping['type'] & ClassMetadataInfo::TO_ONE) {
+                $item       = new AST\PathExpression(AST\PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION, $groupByItem, $mapping['fieldName']);
+                $item->type = AST\PathExpression::TYPE_SINGLE_VALUED_ASSOCIATION;
+
+                $sqlParts[] = $this->walkPathExpression($item);
+            }
+        }
+
+        return implode(', ', $sqlParts);
+    }
+
+    /**
+     * Walks down a DeleteClause AST node, thereby generating the appropriate SQL.
+     *
+     * @param DeleteClause
+     * @return string The SQL.
+     */
+    public function walkDeleteClause(AST\DeleteClause $deleteClause)
+    {
+        $class     = $this->em->getClassMetadata($deleteClause->abstractSchemaName);
+        $tableName = $class->getTableName();
+        $sql       = 'DELETE FROM ' . $this->quoteStrategy->getTableName($class, $this->platform);
+
+        $this->setSQLTableAlias($tableName, $tableName, $deleteClause->aliasIdentificationVariable);
+        $this->rootAliases[] = $deleteClause->aliasIdentificationVariable;
+
+        return $sql;
+    }
+
+    /**
+     * Walks down an UpdateClause AST node, thereby generating the appropriate SQL.
+     *
+     * @param UpdateClause
+     * @return string The SQL.
+     */
+    public function walkUpdateClause($updateClause)
+    {
+        $class     = $this->em->getClassMetadata($updateClause->abstractSchemaName);
+        $tableName = $class->getTableName();
+        $sql       = 'UPDATE ' . $this->quoteStrategy->getTableName($class, $this->platform);
+
+        $this->setSQLTableAlias($tableName, $tableName, $updateClause->aliasIdentificationVariable);
+        $this->rootAliases[] = $updateClause->aliasIdentificationVariable;
+
+        $sql .= ' SET ' . implode(', ', array_map(array($this, 'walkUpdateItem'), $updateClause->updateItems));
+
+        return $sql;
+    }
+
+    /**
+     * Walks down an UpdateItem AST node, thereby generating the appropriate SQL.
+     *
+     * @param UpdateItem
+     * @return string The SQL.
+     */
+    public function walkUpdateItem($updateItem)
+    {
+        $useTableAliasesBefore = $this->useSqlTableAliases;
+        $this->useSqlTableAliases = false;
+
+        $sql      = $this->walkPathExpression($updateItem->pathExpression) . ' = ';
+        $newValue = $updateItem->newValue;
+
+        switch (true) {
+            case ($newValue instanceof AST\Node):
+                $sql .= $newValue->dispatch($this);
+                break;
+
+            case ($newValue === null):
+                $sql .= 'NULL';
+                break;
+
+            default:
+                $sql .= $this->conn->quote($newValue);
+                break;
+        }
+
+        $this->useSqlTableAliases = $useTableAliasesBefore;
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a WhereClause AST node, thereby generating the appropriate SQL.
+     * WhereClause or not, the appropriate discriminator sql is added.
+     *
+     * @param WhereClause
+     * @return string The SQL.
+     */
+    public function walkWhereClause($whereClause)
+    {
+        $condSql  = null !== $whereClause ? $this->walkConditionalExpression($whereClause->conditionalExpression) : '';
+        $discrSql = $this->_generateDiscriminatorColumnConditionSql($this->rootAliases);
+
+        if ($this->em->hasFilters()) {
+            $filterClauses = array();
+            foreach ($this->rootAliases as $dqlAlias) {
+                $class = $this->queryComponents[$dqlAlias]['metadata'];
+                $tableAlias = $this->getSQLTableAlias($class->table['name'], $dqlAlias);
+
+                if ($filterExpr = $this->generateFilterConditionSQL($class, $tableAlias)) {
+                    $filterClauses[] = $filterExpr;
+                }
+            }
+
+            if (count($filterClauses)) {
+                if ($condSql) {
+                    $condSql .= ' AND ';
+                }
+
+                $condSql .= implode(' AND ', $filterClauses);
+            }
+        }
+
+        if ($condSql) {
+            return ' WHERE ' . (( ! $discrSql) ? $condSql : '(' . $condSql . ') AND ' . $discrSql);
+        }
+
+        if ($discrSql) {
+            return ' WHERE ' . $discrSql;
+        }
+
+        return '';
+    }
+
+    /**
+     * Walk down a ConditionalExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param ConditionalExpression
+     * @return string The SQL.
+     */
+    public function walkConditionalExpression($condExpr)
+    {
+        // Phase 2 AST optimization: Skip processment of ConditionalExpression
+        // if only one ConditionalTerm is defined
+        if ( ! ($condExpr instanceof AST\ConditionalExpression)) {
+            return $this->walkConditionalTerm($condExpr);
+        }
+
+        return implode(' OR ', array_map(array($this, 'walkConditionalTerm'), $condExpr->conditionalTerms));
+    }
+
+    /**
+     * Walks down a ConditionalTerm AST node, thereby generating the appropriate SQL.
+     *
+     * @param ConditionalTerm
+     * @return string The SQL.
+     */
+    public function walkConditionalTerm($condTerm)
+    {
+        // Phase 2 AST optimization: Skip processment of ConditionalTerm
+        // if only one ConditionalFactor is defined
+        if ( ! ($condTerm instanceof AST\ConditionalTerm)) {
+            return $this->walkConditionalFactor($condTerm);
+        }
+
+        return implode(' AND ', array_map(array($this, 'walkConditionalFactor'), $condTerm->conditionalFactors));
+    }
+
+    /**
+     * Walks down a ConditionalFactor AST node, thereby generating the appropriate SQL.
+     *
+     * @param ConditionalFactor
+     * @return string The SQL.
+     */
+    public function walkConditionalFactor($factor)
+    {
+        // Phase 2 AST optimization: Skip processment of ConditionalFactor
+        // if only one ConditionalPrimary is defined
+        return ( ! ($factor instanceof AST\ConditionalFactor))
+            ? $this->walkConditionalPrimary($factor)
+            : ($factor->not ? 'NOT ' : '') . $this->walkConditionalPrimary($factor->conditionalPrimary);
+    }
+
+    /**
+     * Walks down a ConditionalPrimary AST node, thereby generating the appropriate SQL.
+     *
+     * @param ConditionalPrimary
+     * @return string The SQL.
+     */
+    public function walkConditionalPrimary($primary)
+    {
+        if ($primary->isSimpleConditionalExpression()) {
+            return $primary->simpleConditionalExpression->dispatch($this);
+        }
+
+        if ($primary->isConditionalExpression()) {
+            $condExpr = $primary->conditionalExpression;
+
+            return '(' . $this->walkConditionalExpression($condExpr) . ')';
+        }
+    }
+
+    /**
+     * Walks down an ExistsExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param ExistsExpression
+     * @return string The SQL.
+     */
+    public function walkExistsExpression($existsExpr)
+    {
+        $sql = ($existsExpr->not) ? 'NOT ' : '';
+
+        $sql .= 'EXISTS (' . $this->walkSubselect($existsExpr->subselect) . ')';
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a CollectionMemberExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param CollectionMemberExpression
+     * @return string The SQL.
+     */
+    public function walkCollectionMemberExpression($collMemberExpr)
+    {
+        $sql = $collMemberExpr->not ? 'NOT ' : '';
+        $sql .= 'EXISTS (SELECT 1 FROM ';
+
+        $entityExpr   = $collMemberExpr->entityExpression;
+        $collPathExpr = $collMemberExpr->collectionValuedPathExpression;
+
+        $fieldName = $collPathExpr->field;
+        $dqlAlias  = $collPathExpr->identificationVariable;
+
+        $class = $this->queryComponents[$dqlAlias]['metadata'];
+
+        switch (true) {
+            // InputParameter
+            case ($entityExpr instanceof AST\InputParameter):
+                $dqlParamKey = $entityExpr->name;
+                $entitySql   = '?';
+                break;
+
+            // SingleValuedAssociationPathExpression | IdentificationVariable
+            case ($entityExpr instanceof AST\PathExpression):
+                $entitySql = $this->walkPathExpression($entityExpr);
+                break;
+
+            default:
+                throw new \BadMethodCallException("Not implemented");
+        }
+
+        $assoc = $class->associationMappings[$fieldName];
+
+        if ($assoc['type'] == ClassMetadata::ONE_TO_MANY) {
+            $targetClass      = $this->em->getClassMetadata($assoc['targetEntity']);
+            $targetTableAlias = $this->getSQLTableAlias($targetClass->getTableName());
+            $sourceTableAlias = $this->getSQLTableAlias($class->getTableName(), $dqlAlias);
+
+            $sql .= $this->quoteStrategy->getTableName($targetClass, $this->platform) . ' ' . $targetTableAlias . ' WHERE ';
+
+            $owningAssoc = $targetClass->associationMappings[$assoc['mappedBy']];
+            $sqlParts    = array();
+
+            foreach ($owningAssoc['targetToSourceKeyColumns'] as $targetColumn => $sourceColumn) {
+                $targetColumn = $this->quoteStrategy->getColumnName($class->fieldNames[$targetColumn], $class, $this->platform);
+
+                $sqlParts[] = $sourceTableAlias . '.' . $targetColumn . ' = ' . $targetTableAlias . '.' . $sourceColumn;
+            }
+
+            foreach ($this->quoteStrategy->getIdentifierColumnNames($targetClass, $this->platform) as $targetColumnName) {
+                if (isset($dqlParamKey)) {
+                    $this->parserResult->addParameterMapping($dqlParamKey, $this->sqlParamIndex++);
+                }
+
+                $sqlParts[] = $targetTableAlias . '.'  . $targetColumnName . ' = ' . $entitySql;
+            }
+
+            $sql .= implode(' AND ', $sqlParts);
+        } else { // many-to-many
+            $targetClass = $this->em->getClassMetadata($assoc['targetEntity']);
+
+            $owningAssoc = $assoc['isOwningSide'] ? $assoc : $targetClass->associationMappings[$assoc['mappedBy']];
+            $joinTable = $owningAssoc['joinTable'];
+
+            // SQL table aliases
+            $joinTableAlias   = $this->getSQLTableAlias($joinTable['name']);
+            $targetTableAlias = $this->getSQLTableAlias($targetClass->getTableName());
+            $sourceTableAlias = $this->getSQLTableAlias($class->getTableName(), $dqlAlias);
+
+            // join to target table
+            $sql .= $this->quoteStrategy->getJoinTableName($owningAssoc, $targetClass, $this->platform) . ' ' . $joinTableAlias
+                  . ' INNER JOIN ' . $this->quoteStrategy->getTableName($targetClass, $this->platform) . ' ' . $targetTableAlias . ' ON ';
+
+            // join conditions
+            $joinColumns  = $assoc['isOwningSide'] ? $joinTable['inverseJoinColumns'] : $joinTable['joinColumns'];
+            $joinSqlParts = array();
+
+            foreach ($joinColumns as $joinColumn) {
+                $targetColumn = $this->quoteStrategy->getColumnName($targetClass->fieldNames[$joinColumn['referencedColumnName']], $targetClass, $this->platform);
+
+                $joinSqlParts[] = $joinTableAlias . '.' . $joinColumn['name'] . ' = ' . $targetTableAlias . '.' . $targetColumn;
+            }
+
+            $sql .= implode(' AND ', $joinSqlParts);
+            $sql .= ' WHERE ';
+
+            $joinColumns = $assoc['isOwningSide'] ? $joinTable['joinColumns'] : $joinTable['inverseJoinColumns'];
+            $sqlParts    = array();
+
+            foreach ($joinColumns as $joinColumn) {
+                $targetColumn = $this->quoteStrategy->getColumnName($class->fieldNames[$joinColumn['referencedColumnName']], $class, $this->platform);
+
+                $sqlParts[] = $joinTableAlias . '.' . $joinColumn['name'] . ' = ' . $sourceTableAlias . '.' . $targetColumn;
+            }
+
+            foreach ($this->quoteStrategy->getIdentifierColumnNames($targetClass, $this->platform) as $targetColumnName) {
+                if (isset($dqlParamKey)) {
+                    $this->parserResult->addParameterMapping($dqlParamKey, $this->sqlParamIndex++);
+                }
+
+                $sqlParts[] = $targetTableAlias . '.' . $targetColumnName . ' = ' . $entitySql;
+            }
+
+            $sql .= implode(' AND ', $sqlParts);
+        }
+
+        return $sql . ')';
+    }
+
+    /**
+     * Walks down an EmptyCollectionComparisonExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param EmptyCollectionComparisonExpression
+     * @return string The SQL.
+     */
+    public function walkEmptyCollectionComparisonExpression($emptyCollCompExpr)
+    {
+        $sizeFunc = new AST\Functions\SizeFunction('size');
+        $sizeFunc->collectionPathExpression = $emptyCollCompExpr->expression;
+
+        return $sizeFunc->getSql($this) . ($emptyCollCompExpr->not ? ' > 0' : ' = 0');
+    }
+
+    /**
+     * Walks down a NullComparisonExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param NullComparisonExpression
+     * @return string The SQL.
+     */
+    public function walkNullComparisonExpression($nullCompExpr)
+    {
+        $sql = '';
+        $innerExpr = $nullCompExpr->expression;
+
+        if ($innerExpr instanceof AST\InputParameter) {
+            $dqlParamKey = $innerExpr->name;
+            $this->parserResult->addParameterMapping($dqlParamKey, $this->sqlParamIndex++);
+            $sql .= ' ?';
+        } else {
+            $sql .= $this->walkPathExpression($innerExpr);
+        }
+
+        $sql .= ' IS' . ($nullCompExpr->not ? ' NOT' : '') . ' NULL';
+
+        return $sql;
+    }
+
+    /**
+     * Walks down an InExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param InExpression
+     * @return string The SQL.
+     */
+    public function walkInExpression($inExpr)
+    {
+        $sql = $this->walkArithmeticExpression($inExpr->expression) . ($inExpr->not ? ' NOT' : '') . ' IN (';
+
+        $sql .= ($inExpr->subselect)
+            ? $this->walkSubselect($inExpr->subselect)
+            : implode(', ', array_map(array($this, 'walkInParameter'), $inExpr->literals));
+
+        $sql .= ')';
+
+        return $sql;
+    }
+
+    /**
+     * Walks down an InstanceOfExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param InstanceOfExpression
+     * @return string The SQL.
+     */
+    public function walkInstanceOfExpression($instanceOfExpr)
+    {
+        $sql = '';
+
+        $dqlAlias = $instanceOfExpr->identificationVariable;
+        $discrClass = $class = $this->queryComponents[$dqlAlias]['metadata'];
+        
+        if ($class->discriminatorColumn) {
+            $discrClass = $this->em->getClassMetadata($class->rootEntityName);
+        }
+
+        if ($this->useSqlTableAliases) {
+            $sql .= $this->getSQLTableAlias($discrClass->getTableName(), $dqlAlias) . '.';
+        }
+
+        $sql .= $class->discriminatorColumn['name'] . ($instanceOfExpr->not ? ' NOT IN ' : ' IN ');
+
+        $sqlParameterList = array();
+
+        foreach ($instanceOfExpr->value as $parameter) {
+            if ($parameter instanceof AST\InputParameter) {
+                // We need to modify the parameter value to be its correspondent mapped value
+                $dqlParamKey = $parameter->name;
+                $dqlParam    = $this->query->getParameter($dqlParamKey);
+                $paramValue  = $this->query->processParameterValue($dqlParam->getValue());
+
+                if ( ! ($paramValue instanceof \Doctrine\ORM\Mapping\ClassMetadata)) {
+                    throw QueryException::invalidParameterType('ClassMetadata', get_class($paramValue));
+                }
+
+                $entityClassName = $paramValue->name;
+            } else {
+                // Get name from ClassMetadata to resolve aliases.
+                $entityClassName = $this->em->getClassMetadata($parameter)->name;
+            }
+
+            if ($entityClassName == $class->name) {
+                $sqlParameterList[] = $this->conn->quote($class->discriminatorValue);
+            } else {
+                $discrMap = array_flip($class->discriminatorMap);
+
+                if (!isset($discrMap[$entityClassName])) {
+                    throw QueryException::instanceOfUnrelatedClass($entityClassName, $class->rootEntityName);
+                }
+
+                $sqlParameterList[] = $this->conn->quote($discrMap[$entityClassName]);
+            }
+        }
+
+        $sql .= '(' . implode(', ', $sqlParameterList) . ')';
+
+        return $sql;
+    }
+
+    /**
+     * Walks down an InParameter AST node, thereby generating the appropriate SQL.
+     *
+     * @param InParameter
+     * @return string The SQL.
+     */
+    public function walkInParameter($inParam)
+    {
+        return $inParam instanceof AST\InputParameter
+            ? $this->walkInputParameter($inParam)
+            : $this->walkLiteral($inParam);
+    }
+
+    /**
+     * Walks down a literal that represents an AST node, thereby generating the appropriate SQL.
+     *
+     * @param mixed
+     * @return string The SQL.
+     */
+    public function walkLiteral($literal)
+    {
+        switch ($literal->type) {
+            case AST\Literal::STRING:
+                return $this->conn->quote($literal->value);
+
+            case AST\Literal::BOOLEAN:
+                $bool = strtolower($literal->value) == 'true' ? true : false;
+                $boolVal = $this->conn->getDatabasePlatform()->convertBooleans($bool);
+
+                return $boolVal;
+
+            case AST\Literal::NUMERIC:
+                return $literal->value;
+
+            default:
+                throw QueryException::invalidLiteral($literal);
+        }
+    }
+
+    /**
+     * Walks down a BetweenExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param BetweenExpression
+     * @return string The SQL.
+     */
+    public function walkBetweenExpression($betweenExpr)
+    {
+        $sql = $this->walkArithmeticExpression($betweenExpr->expression);
+
+        if ($betweenExpr->not) $sql .= ' NOT';
+
+        $sql .= ' BETWEEN ' . $this->walkArithmeticExpression($betweenExpr->leftBetweenExpression)
+              . ' AND ' . $this->walkArithmeticExpression($betweenExpr->rightBetweenExpression);
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a LikeExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param LikeExpression
+     * @return string The SQL.
+     */
+    public function walkLikeExpression($likeExpr)
+    {
+        $stringExpr = $likeExpr->stringExpression;
+        $sql = $stringExpr->dispatch($this) . ($likeExpr->not ? ' NOT' : '') . ' LIKE ';
+
+        if ($likeExpr->stringPattern instanceof AST\InputParameter) {
+            $inputParam = $likeExpr->stringPattern;
+            $dqlParamKey = $inputParam->name;
+            $this->parserResult->addParameterMapping($dqlParamKey, $this->sqlParamIndex++);
+            $sql .= '?';
+        } elseif ($likeExpr->stringPattern instanceof AST\Functions\FunctionNode ) {
+            $sql .= $this->walkFunction($likeExpr->stringPattern);
+        } elseif ($likeExpr->stringPattern instanceof AST\PathExpression) {
+            $sql .= $this->walkPathExpression($likeExpr->stringPattern);
+        } else {
+            $sql .= $this->walkLiteral($likeExpr->stringPattern);
+        }
+
+        if ($likeExpr->escapeChar) {
+            $sql .= ' ESCAPE ' . $this->walkLiteral($likeExpr->escapeChar);
+        }
+
+        return $sql;
+    }
+
+    /**
+     * Walks down a StateFieldPathExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param StateFieldPathExpression
+     * @return string The SQL.
+     */
+    public function walkStateFieldPathExpression($stateFieldPathExpression)
+    {
+        return $this->walkPathExpression($stateFieldPathExpression);
+    }
+
+    /**
+     * Walks down a ComparisonExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param ComparisonExpression
+     * @return string The SQL.
+     */
+    public function walkComparisonExpression($compExpr)
+    {
+        $leftExpr  = $compExpr->leftExpression;
+        $rightExpr = $compExpr->rightExpression;
+        $sql       = '';
+
+        $sql .= ($leftExpr instanceof AST\Node)
+            ? $leftExpr->dispatch($this)
+            : (is_numeric($leftExpr) ? $leftExpr : $this->conn->quote($leftExpr));
+
+        $sql .= ' ' . $compExpr->operator . ' ';
+
+        $sql .= ($rightExpr instanceof AST\Node)
+            ? $rightExpr->dispatch($this)
+            : (is_numeric($rightExpr) ? $rightExpr : $this->conn->quote($rightExpr));
+
+        return $sql;
+    }
+
+    /**
+     * Walks down an InputParameter AST node, thereby generating the appropriate SQL.
+     *
+     * @param InputParameter
+     * @return string The SQL.
+     */
+    public function walkInputParameter($inputParam)
+    {
+        $this->parserResult->addParameterMapping($inputParam->name, $this->sqlParamIndex++);
+
+        return '?';
+    }
+
+    /**
+     * Walks down an ArithmeticExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param ArithmeticExpression
+     * @return string The SQL.
+     */
+    public function walkArithmeticExpression($arithmeticExpr)
+    {
+        return ($arithmeticExpr->isSimpleArithmeticExpression())
+            ? $this->walkSimpleArithmeticExpression($arithmeticExpr->simpleArithmeticExpression)
+            : '(' . $this->walkSubselect($arithmeticExpr->subselect) . ')';
+    }
+
+    /**
+     * Walks down an SimpleArithmeticExpression AST node, thereby generating the appropriate SQL.
+     *
+     * @param SimpleArithmeticExpression
+     * @return string The SQL.
+     */
+    public function walkSimpleArithmeticExpression($simpleArithmeticExpr)
+    {
+        if ( ! ($simpleArithmeticExpr instanceof AST\SimpleArithmeticExpression)) {
+            return $this->walkArithmeticTerm($simpleArithmeticExpr);
+        }
+
+        return implode(' ', array_map(array($this, 'walkArithmeticTerm'), $simpleArithmeticExpr->arithmeticTerms));
+    }
+
+    /**
+     * Walks down an ArithmeticTerm AST node, thereby generating the appropriate SQL.
+     *
+     * @param mixed
+     * @return string The SQL.
+     */
+    public function walkArithmeticTerm($term)
+    {
+        if (is_string($term)) {
+            return (isset($this->queryComponents[$term]))
+                ? $this->walkResultVariable($this->queryComponents[$term]['token']['value'])
+                : $term;
+        }
+
+        // Phase 2 AST optimization: Skip processment of ArithmeticTerm
+        // if only one ArithmeticFactor is defined
+        if ( ! ($term instanceof AST\ArithmeticTerm)) {
+            return $this->walkArithmeticFactor($term);
+        }
+
+        return implode(' ', array_map(array($this, 'walkArithmeticFactor'), $term->arithmeticFactors));
+    }
+
+    /**
+     * Walks down an ArithmeticFactor that represents an AST node, thereby generating the appropriate SQL.
+     *
+     * @param mixed
+     * @return string The SQL.
+     */
+    public function walkArithmeticFactor($factor)
+    {
+        if (is_string($factor)) {
+            return $factor;
+        }
+
+        // Phase 2 AST optimization: Skip processment of ArithmeticFactor
+        // if only one ArithmeticPrimary is defined
+        if ( ! ($factor instanceof AST\ArithmeticFactor)) {
+            return $this->walkArithmeticPrimary($factor);
+        }
+
+        $sign = $factor->isNegativeSigned() ? '-' : ($factor->isPositiveSigned() ? '+' : '');
+
+        return $sign . $this->walkArithmeticPrimary($factor->arithmeticPrimary);
+    }
+
+    /**
+     * Walks down an ArithmeticPrimary that represents an AST node, thereby generating the appropriate SQL.
+     *
+     * @param mixed
+     * @return string The SQL.
+     */
+    public function walkArithmeticPrimary($primary)
+    {
+        if ($primary instanceof AST\SimpleArithmeticExpression) {
+            return '(' . $this->walkSimpleArithmeticExpression($primary) . ')';
+        }
+
+        if ($primary instanceof AST\Node) {
+            return $primary->dispatch($this);
+        }
+
+        return $this->walkEntityIdentificationVariable($primary);
+    }
+
+    /**
+     * Walks down a StringPrimary that represents an AST node, thereby generating the appropriate SQL.
+     *
+     * @param mixed
+     * @return string The SQL.
+     */
+    public function walkStringPrimary($stringPrimary)
+    {
+        return (is_string($stringPrimary))
+            ? $this->conn->quote($stringPrimary)
+            : $stringPrimary->dispatch($this);
+    }
+
+    /**
+     * Walks down a ResultVriable that represents an AST node, thereby generating the appropriate SQL.
+     *
+     * @param string $resultVariable
+     * @return string The SQL.
+     */
+    public function walkResultVariable($resultVariable)
+    {
+        $resultAlias = $this->scalarResultAliasMap[$resultVariable];
+
+        if (is_array($resultAlias)) {
+            return implode(', ', $resultAlias);
+        }
+
+        return $resultAlias;
+    }
+}