diff --git a/lib/Doctrine/Common/DataFixtures/AbstractFixture.php b/lib/Doctrine/Common/DataFixtures/AbstractFixture.php
index ac5976e2..1e7fb674 100644
--- a/lib/Doctrine/Common/DataFixtures/AbstractFixture.php
+++ b/lib/Doctrine/Common/DataFixtures/AbstractFixture.php
@@ -63,11 +63,14 @@ public function setReference($name, $object)
     /**
      * Set the reference entry identified by $name
      * and referenced to managed $object. If $name
-     * already is set, it overrides it
+     * already is set, it throws a 
+     * BadMethodCallException exception
      * 
      * @param string $name
      * @param object $object - managed object
      * @see Doctrine\Common\DataFixtures\ReferenceRepository::addReference
+     * @throws BadMethodCallException - if repository already has
+     *      a reference by $name
      * @return void
      */
     public function addReference($name, $object)
diff --git a/lib/Doctrine/Common/DataFixtures/FixtureInterface.php b/lib/Doctrine/Common/DataFixtures/FixtureInterface.php
index 9b0a8b4c..3d66bf46 100644
--- a/lib/Doctrine/Common/DataFixtures/FixtureInterface.php
+++ b/lib/Doctrine/Common/DataFixtures/FixtureInterface.php
@@ -31,7 +31,7 @@ interface FixtureInterface
     /**
      * Load data fixtures with the passed EntityManager
      *
-     * @param Doctrine\Common\Persistence\ObjectManager $manager
+     * @param ObjectManager $manager
      */
-    function load(ObjectManager $manager);
+    public function load(ObjectManager $manager);
 }
diff --git a/lib/Doctrine/Common/DataFixtures/ProxyReferenceRepository.php b/lib/Doctrine/Common/DataFixtures/ProxyReferenceRepository.php
index 9bc5dd4b..baf0bed7 100644
--- a/lib/Doctrine/Common/DataFixtures/ProxyReferenceRepository.php
+++ b/lib/Doctrine/Common/DataFixtures/ProxyReferenceRepository.php
@@ -28,6 +28,7 @@
  * Allow data fixture references and identities to be persisted when cached data fixtures
  * are pre-loaded, for example, by LiipFunctionalTestBundle\Test\WebTestCase loadFixtures().
  *
+ * @author Guilherme Blanco <guilhermeblanco@hotmail.com>
  * @author Anthon Pang <anthonp@nationalfibre.net>
  */
 class ProxyReferenceRepository extends ReferenceRepository
@@ -59,12 +60,13 @@ protected function getRealClass($className)
      */
     public function serialize()
     {
+        $unitOfWork       = $this->getManager()->getUnitOfWork();
         $simpleReferences = array();
 
         foreach ($this->getReferences() as $name => $reference) {
             $className = $this->getRealClass(get_class($reference));
 
-            $simpleReferences[$name] = array($className, $reference->getId());
+            $simpleReferences[$name] = array($className, $this->getIdentifier($reference, $unitOfWork));
         }
 
         $serializedData = json_encode(array(
@@ -90,7 +92,7 @@ public function unserialize($serializedData)
                 $name,
                 $this->getManager()->getReference(
                     $proxyReference[0], // entity class name
-                    $proxyReference[1]  // id
+                    $proxyReference[1]  // identifiers
                 )
             );
         }
diff --git a/lib/Doctrine/Common/DataFixtures/Purger/ORMPurger.php b/lib/Doctrine/Common/DataFixtures/Purger/ORMPurger.php
index 658b3d49..305f2616 100644
--- a/lib/Doctrine/Common/DataFixtures/Purger/ORMPurger.php
+++ b/lib/Doctrine/Common/DataFixtures/Purger/ORMPurger.php
@@ -19,6 +19,7 @@
 
 namespace Doctrine\Common\DataFixtures\Purger;
 
+use Doctrine\DBAL\Platforms\MySqlPlatform;
 use Doctrine\ORM\EntityManager;
 use Doctrine\ORM\Internal\CommitOrderCalculator;
 use Doctrine\ORM\Mapping\ClassMetadata;
@@ -127,6 +128,10 @@ public function purge()
             $orderedTables[] = $class->getQuotedTableName($platform);
         }
 
+        if ($platform instanceof MySqlPlatform) {
+            $this->setForeignKeyChecks(false);
+        }
+
         foreach($orderedTables as $tbl) {
             if ($this->purgeMode === self::PURGE_MODE_DELETE) {
                 $this->em->getConnection()->executeUpdate("DELETE FROM " . $tbl);
@@ -134,6 +139,10 @@ public function purge()
                 $this->em->getConnection()->executeUpdate($platform->getTruncateTableSQL($tbl, true));
             }
         }
+
+        if ($platform instanceof MySqlPlatform) {
+            $this->setForeignKeyChecks(true);
+        }
     }
 
     private function getCommitOrder(EntityManager $em, array $classes)
@@ -196,4 +205,18 @@ private function getAssociationTables(array $classes)
 
         return $associationTables;
     }
+
+    /**
+     * Enable/disable foreign key checks on the MySQL platform
+     *
+     * @param bool $bool
+     */
+    private function setForeignKeyChecks($bool)
+    {
+        if ($this->purgeMode !== self::PURGE_MODE_TRUNCATE) {
+            return;
+        }
+
+        $this->em->getConnection()->query(sprintf('SET FOREIGN_KEY_CHECKS=%s', (int) $bool));
+    }
 }
diff --git a/lib/Doctrine/Common/DataFixtures/ReferenceRepository.php b/lib/Doctrine/Common/DataFixtures/ReferenceRepository.php
index 1cac6e38..290f2212 100644
--- a/lib/Doctrine/Common/DataFixtures/ReferenceRepository.php
+++ b/lib/Doctrine/Common/DataFixtures/ReferenceRepository.php
@@ -70,14 +70,23 @@ public function __construct(ObjectManager $manager)
      * @param object $reference Reference object
      * @param object $uow       Unit of work
      *
-     * @return mixed
+     * @return array
      */
     protected function getIdentifier($reference, $uow)
     {
+        // In case Reference is not yet managed in UnitOfWork
+        if ( ! $uow->isInIdentityMap($reference)) {
+            $class = $this->manager->getClassMetadata(get_class($reference));
+
+            return $class->getIdentifierValues($reference);
+        }
+
+        // Dealing with ORM UnitOfWork
         if (method_exists($uow, 'getEntityIdentifier')) {
             return $uow->getEntityIdentifier($reference);
         }
 
+        // ODM UnitOfWork
         return $uow->getDocumentIdentifier($reference);
     }