diff --git a/lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php b/lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php
index 146dfb5c5..6c095c9e3 100644
--- a/lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php
+++ b/lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php
@@ -245,6 +245,9 @@ abstract class AbstractHydrator
             if (isset($cache[$key]['isMetaColumn'])) {
                 if ( ! isset($rowData[$dqlAlias][$cache[$key]['fieldName']]) || $value !== null) {
                     $rowData[$dqlAlias][$cache[$key]['fieldName']] = $value;
+                    if ($cache[$key]['isIdentifier']) {
+                        $nonemptyComponents[$dqlAlias] = true;
+                    }
                 }
 
                 continue;
diff --git a/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1515Test.php b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1515Test.php
new file mode 100644
index 000000000..9bd3360b8
--- /dev/null
+++ b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1515Test.php
@@ -0,0 +1,64 @@
+<?php
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+
+/**
+ * @group DDC-1515
+ */
+class DDC1515Test extends \Doctrine\Tests\OrmFunctionalTestCase
+{
+    public function setUp()
+    {
+        parent::setUp();
+        $this->_schemaTool->createSchema(array(
+            $this->_em->getClassMetadata(__NAMESPACE__ . '\\DDC1515Foo'),
+            $this->_em->getClassMetadata(__NAMESPACE__ . '\\DDC1515Bar'),
+        ));
+    }
+
+    public function testIssue()
+    {
+        $bar = new DDC1515Bar();
+        $this->_em->persist($bar);
+        $this->_em->flush();
+
+        $foo = new DDC1515Foo();
+        $foo->bar = $bar;
+        $this->_em->persist($foo);
+        $this->_em->flush();
+        $this->_em->clear();
+
+        $bar = $this->_em->find(__NAMESPACE__ . '\DDC1515Bar', $bar->id);
+        $this->assertInstanceOf(__NAMESPACE__.'\DDC1515Foo', $bar->foo);
+    }
+}
+
+/**
+ * @Entity
+ */
+class DDC1515Foo
+{
+    /**
+     * @OneToOne(targetEntity="DDC1515Bar", inversedBy="foo") @Id
+     */
+    public $bar;
+}
+
+/**
+ * @Entity
+ */
+class DDC1515Bar
+{
+    /**
+     * @Id @Column(type="integer") @GeneratedValue
+     */
+    public $id;
+
+    /**
+     * @OneToOne(targetEntity="DDC1515Foo", mappedBy="bar")
+     */
+    public $foo;
+}
+
+