diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/hibernate/NullBridge.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/hibernate/NullBridge.java
index 0bd135cdd3230e0d001f1ddd2014911fca284305..27efe6b1e300c7cf09a841ec038ebbe021b21451 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/hibernate/NullBridge.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/hibernate/NullBridge.java
@@ -24,7 +24,7 @@ import org.hibernate.search.bridge.builtin.LongBridge;
 public class NullBridge extends LongBridge
 {
 
-    public static final String NULL = "NULLNULL";
+    public static final String NULL = "NULL";
 
     @Override
     public String objectToString(Object object)