diff --git a/src/helma/objectmodel/db/Node.java b/src/helma/objectmodel/db/Node.java
index e60d90ec..a7dff481 100644
--- a/src/helma/objectmodel/db/Node.java
+++ b/src/helma/objectmodel/db/Node.java
@@ -2369,11 +2369,13 @@ public final class Node implements INode, Serializable {
 
         Relation rel = (dbmap == null) ? null : dbmap.getPropertyRelation(propname);
 
-        if (rel != null && rel.isComplexReference()) {
+        if (rel != null && (rel.countConstraints() > 1 || rel.isComplexReference())) {
             rel.setConstraints(this, n);
-            Key key = new MultiKey(n.getDbMapping(), rel.getKeyParts(this));
-            nmgr.nmgr.registerNode(n, key);
-            return;
+            if (rel.isComplexReference()) {
+                Key key = new MultiKey(n.getDbMapping(), rel.getKeyParts(this));
+                nmgr.nmgr.registerNode(n, key);
+                return;
+            }
         }
 
         Property prop = (propMap == null) ? null : (Property) propMap.get(p2);
@@ -2485,6 +2487,15 @@ public final class Node implements INode, Serializable {
                 if (state == CLEAN) {
                     markAs(MODIFIED);
                 }
+            } else if (dbmap != null) {
+                // check if this is a complex constraint and we have to
+                // unset constraints.
+                Relation rel = dbmap.getExactPropertyRelation(propname);
+
+                if (rel != null && (rel.isComplexReference() || rel.countConstraints() > 1)) {
+                    p = getProperty(propname);
+                    System.err.println ("NEED TO UNSET: "+p.getNodeValue());
+                }
             }
         } catch (Exception ignore) {
         }
diff --git a/src/helma/objectmodel/db/Relation.java b/src/helma/objectmodel/db/Relation.java
index f02d4c66..6bbda01b 100644
--- a/src/helma/objectmodel/db/Relation.java
+++ b/src/helma/objectmodel/db/Relation.java
@@ -176,7 +176,7 @@ public final class Relation {
 
             // check if this is a non-trivial reference
             if (reftype == REFERENCE) {
-                if (constraints.length > 1 || !usesPrimaryKey()) {
+                if (constraints.length > 0 && !usesPrimaryKey()) {
                     reftype = COMPLEX_REFERENCE;
                 }
             }
@@ -323,6 +323,15 @@ public final class Relation {
         return isPrivate;
     }
 
+    /**
+     *  Returns the number of constraints for this relation.
+     */
+    public int countConstraints() {
+        if (constraints == null)
+            return 0;
+        return constraints.length;
+    }
+
     /**
      *  Returns true if the object represented by this Relation has to be
      *  created dynamically by the Helma objectmodel runtime as a virtual