fix for #9

src/main/java/org/etsi/osl/model/nfv/ConstituentVxF.java

@@ -52,7 +52,7 @@ public class ConstituentVxF {
 	@Basic()
 	private String vnfdidRef;
 	
-	@ManyToOne(cascade = { CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH, CascadeType.DETACH } )
+	@ManyToOne(cascade = { CascadeType.DETACH } )
 	@JoinColumn(name = "vxf_id")
 	private VxFMetadata vxfref;