diff --git a/lib/Doctrine/ORM/Internal/Hydration/HydrationException.php b/lib/Doctrine/ORM/Internal/Hydration/HydrationException.php
index 886b42dec..147f6acae 100644
--- a/lib/Doctrine/ORM/Internal/Hydration/HydrationException.php
+++ b/lib/Doctrine/ORM/Internal/Hydration/HydrationException.php
@@ -8,10 +8,19 @@ class HydrationException extends \Doctrine\ORM\ORMException
     {
         return new self("The result returned by the query was not unique.");
     }
-    
+
     public static function parentObjectOfRelationNotFound($alias, $parentAlias)
     {
         return new self("The parent object of entity result with alias '$alias' was not found."
                 . " The parent alias is '$parentAlias'.");
     }
+
+    public static function emptyDiscriminatorValue($dqlAlias)
+    {
+        return new self("The DQL alias '" . $dqlAlias . "' contains an entity ".
+            "of an inheritance hierachy with an empty discriminator value. This means " .
+            "that the database contains inconsistent data with an empty " .
+            "discriminator value in a table row."
+        );
+    }
 }
\ No newline at end of file
diff --git a/lib/Doctrine/ORM/Internal/Hydration/ObjectHydrator.php b/lib/Doctrine/ORM/Internal/Hydration/ObjectHydrator.php
index 1bd16164b..3f787694b 100644
--- a/lib/Doctrine/ORM/Internal/Hydration/ObjectHydrator.php
+++ b/lib/Doctrine/ORM/Internal/Hydration/ObjectHydrator.php
@@ -202,6 +202,11 @@ class ObjectHydrator extends AbstractHydrator
         $className = $this->_rsm->aliasMap[$dqlAlias];
         if (isset($this->_rsm->discriminatorColumns[$dqlAlias])) {
             $discrColumn = $this->_rsm->metaMappings[$this->_rsm->discriminatorColumns[$dqlAlias]];
+
+            if ($data[$discrColumn] === "") {
+                throw HydrationException::emptyDiscriminatorValue($dqlAlias);
+            }
+
             $className = $this->_ce[$className]->discriminatorMap[$data[$discrColumn]];
             unset($data[$discrColumn]);
         }
diff --git a/lib/Doctrine/ORM/Internal/Hydration/SimpleObjectHydrator.php b/lib/Doctrine/ORM/Internal/Hydration/SimpleObjectHydrator.php
index 34d8e31b1..e9f6395f9 100644
--- a/lib/Doctrine/ORM/Internal/Hydration/SimpleObjectHydrator.php
+++ b/lib/Doctrine/ORM/Internal/Hydration/SimpleObjectHydrator.php
@@ -89,8 +89,13 @@ class SimpleObjectHydrator extends AbstractHydrator
             $entityName = $this->class->name;
         } else {
             $discrColumnName = $this->_platform->getSQLResultCasing($this->class->discriminatorColumn['name']);
+            if ($sqlResult[$discrColumnName] === "") {
+                throw HydrationException::emptyDiscriminatorValue(key($this->_rsm->aliasMap));
+            }
+
             $entityName = $this->class->discriminatorMap[$sqlResult[$discrColumnName]];
             unset($sqlResult[$discrColumnName]);
+
             foreach ($sqlResult as $column => $value) {
                 if (!isset($cache[$column])) {
                     if (isset($this->_rsm->fieldMappings[$column])) {