diff --git a/src/main/java/org/gcube/portlets/user/td/gwtservice/shared/Constants.java b/src/main/java/org/gcube/portlets/user/td/gwtservice/shared/Constants.java
index e44f1c3..ee6f019 100644
--- a/src/main/java/org/gcube/portlets/user/td/gwtservice/shared/Constants.java
+++ b/src/main/java/org/gcube/portlets/user/td/gwtservice/shared/Constants.java
@@ -44,7 +44,7 @@ public class Constants {
 	
 	public static final String PARAMETER_UNION_COMPOSITE_SOURCE = "source";
 	public static final String PARAMETER_UNION_COMPOSITE_TARGET = "target";
-	public static final String PARAMETER_UNION_COMPOSITE = "mapping";
+	public static final String PARAMETER_UNION_COMPOSITE = "mappings";
 
 	
 	public static final String PARAMETER_ADD_ROW_COMPOSITE_FIELD = "field";