diff --git a/src/helma/objectmodel/db/DbMapping.java b/src/helma/objectmodel/db/DbMapping.java
index 10b84244..d2186c25 100644
--- a/src/helma/objectmodel/db/DbMapping.java
+++ b/src/helma/objectmodel/db/DbMapping.java
@@ -26,8 +26,6 @@ public final class DbMapping implements Updatable {
     // prototype name of this mapping
     String typename;
 
-    // int version;
-
     // properties from where the mapping is read
     SystemProperties props;
 
@@ -42,8 +40,8 @@ public final class DbMapping implements Updatable {
     ParentInfo[] parent;
 
     // Relations describing subnodes and properties.
-    Relation subnodesRel;
-    Relation propertiesRel;
+    Relation subRelation;
+    Relation propRelation;
 
     // if this defines a subnode mapping with groupby layer, we need a DbMapping for those groupby nodes
     DbMapping groupbyMapping;
@@ -230,17 +228,19 @@ public final class DbMapping implements Updatable {
 	if (subnodeMapping != null) {
 	    try {
 	        // check if subnode relation already exists. If so, reuse it
-	        if (subnodesRel == null)
-	            subnodesRel = new Relation (subnodeMapping, "_children", this, props);
-	        subnodesRel.update (subnodeMapping, props);
-	        if (subnodesRel.accessor != null)
-	            propertiesRel = subnodesRel;
+	        if (subRelation == null)
+	            subRelation = new Relation (subnodeMapping, "_children", this, props);
+	        subRelation.update (subnodeMapping, props);
+	        // if subnodes are accessed via access name or group name, 
+	        // the subnode relation is also the property relation.
+	        if (subRelation.accessor != null || subRelation.groupby != null)
+	            propRelation = subRelation;
 	    } catch (Exception x) {
 	        app.logEvent ("Error reading _subnodes relation for "+typename+": "+x.getMessage ());
-	        // subnodesRel = null;
+	        // subRelation = null;
 	    }
 	} else {
-	    subnodesRel = propertiesRel = null;
+	    subRelation = propRelation = null;
 	}
 
 	if (groupbyMapping != null) {
@@ -422,8 +422,8 @@ public final class DbMapping implements Updatable {
 
 
     public DbMapping getSubnodeMapping () {
-	if (subnodesRel != null)
-	    return subnodesRel.otherType;
+	if (subRelation != null)
+	    return subRelation.otherType;
     	if (parentMapping != null)
     	    return parentMapping.getSubnodeMapping ();
 	return null;
@@ -452,7 +452,7 @@ public final class DbMapping implements Updatable {
      * db-mapping with the right relations to create the group-by nodes
      */
     public synchronized DbMapping getGroupbyMapping () {
-	if (subnodesRel == null || subnodesRel.groupby == null)
+	if (subRelation == null || subRelation.groupby == null)
 	    return null;
 	if (groupbyMapping == null) {
 	    initGroupbyMapping ();
@@ -469,38 +469,31 @@ public final class DbMapping implements Updatable {
 	groupbyMapping = new DbMapping (app);
 	// If a mapping is defined, make the internal mapping inherit from
 	// the defined named prototype.
-	if (subnodesRel.groupbyprototype != null)
-	    groupbyMapping.parentMapping = app.getDbMapping (subnodesRel.groupbyprototype);
-	groupbyMapping.subnodesRel = subnodesRel.getGroupbySubnodeRelation ();
-	if (propertiesRel != null)
-	    groupbyMapping.propertiesRel = propertiesRel.getGroupbyPropertyRelation ();
+	if (subRelation.groupbyPrototype != null)
+	    groupbyMapping.parentMapping = app.getDbMapping (subRelation.groupbyPrototype);
+	groupbyMapping.subRelation = subRelation.getGroupbySubnodeRelation ();
+	if (propRelation != null)
+	    groupbyMapping.propRelation = propRelation.getGroupbyPropertyRelation ();
 	else
-	    groupbyMapping.propertiesRel = subnodesRel.getGroupbyPropertyRelation ();
-	groupbyMapping.typename = subnodesRel.groupbyprototype;
+	    groupbyMapping.propRelation = subRelation.getGroupbyPropertyRelation ();
+	groupbyMapping.typename = subRelation.groupbyPrototype;
     }
 
-    /* public void setPropertyMapping (DbMapping pm) {
-	properties = pm;
-    } */
-
-    /* public void setSubnodeRelation (Relation rel) {
-	subnodesRel = rel;
-    } */
-
+    
     public void setPropertyRelation (Relation rel) {
-	propertiesRel = rel;
+	propRelation = rel;
     }
 
     public Relation getSubnodeRelation () {
-	if (subnodesRel == null && parentMapping != null)
+	if (subRelation == null && parentMapping != null)
 	    return parentMapping.getSubnodeRelation ();
-	return subnodesRel;
+	return subRelation;
     }
 
     public Relation getPropertyRelation () {
-	if (propertiesRel == null && parentMapping != null)
+	if (propRelation == null && parentMapping != null)
 	    return parentMapping.getPropertyRelation ();
-	return propertiesRel;
+	return propRelation;
     }
 
     public Relation getPropertyRelation (String propname) {
@@ -524,9 +517,9 @@ public final class DbMapping implements Updatable {
     }
 
     public String getSubnodeGroupby () {
-	if (subnodesRel == null && parentMapping != null)
+	if (subRelation == null && parentMapping != null)
 	    return parentMapping.getSubnodeGroupby ();
-	return subnodesRel == null ? null : subnodesRel.groupby;
+	return subRelation == null ? null : subRelation.groupby;
     }
 
     public String getIDgen () {
diff --git a/src/helma/objectmodel/db/Node.java b/src/helma/objectmodel/db/Node.java
index dba3415d..08a829f5 100644
--- a/src/helma/objectmodel/db/Node.java
+++ b/src/helma/objectmodel/db/Node.java
@@ -17,7 +17,6 @@ import helma.objectmodel.*;
 import helma.util.*;
 import helma.framework.IPathElement;
 import java.math.BigDecimal;
-// import com.workingdogs.village.*;
 
 
 /**
@@ -154,7 +153,7 @@ public final class Node implements INode, Serializable {
     transient String subnodeRelation = null;
     transient long lastSubnodeFetch = 0;
     transient long lastSubnodeChange = 0;
-
+    transient long lastNameCheck = 0;
     transient long lastParentSet = 0;
 
     transient long lastSubnodeCount = 0;  // these two are only used
@@ -261,11 +260,6 @@ public final class Node implements INode, Serializable {
 	name = nameField == null ? id : rs.getString (nameField);
 	if (name == null || name.length() == 0)
 	    name = dbmap.getTypeName() + " " + id;
-	// set parent for user objects to internal userroot node
-	if ("user".equals (prototype)) {
-	    parentHandle = new NodeHandle (new DbKey (null, "1"));
-	    anonymous = false;
-	}
 
 	created = lastmodified = System.currentTimeMillis ();
 
@@ -281,25 +275,25 @@ public final class Node implements INode, Serializable {
 	    switch (rel.getColumnType()) {
 
 	        case Types.BIT:
-	            newprop.setBooleanValue (rs.getBoolean(rel.getDbField()));
+	            newprop.setBooleanValue (rs.getBoolean(columns[i]));
 	            break;
 
 	        case Types.TINYINT:
 	        case Types.BIGINT:
 	        case Types.SMALLINT:
 	        case Types.INTEGER:
-	            newprop.setIntegerValue (rs.getLong(rel.getDbField()));
+	            newprop.setIntegerValue (rs.getLong(columns[i]));
 	            break;
 
 	        case Types.REAL:
 	        case Types.FLOAT:
 	        case Types.DOUBLE:
-	            newprop.setFloatValue (rs.getDouble(rel.getDbField()));
+	            newprop.setFloatValue (rs.getDouble(columns[i]));
 	            break;
 
 	        case Types.DECIMAL:
 	        case Types.NUMERIC:
-	            BigDecimal num = rs.getBigDecimal (rel.getDbField());
+	            BigDecimal num = rs.getBigDecimal (columns[i]);
 	            if (num == null) 
 	                break;
 	            if (num.scale() > 0)
@@ -311,20 +305,20 @@ public final class Node implements INode, Serializable {
 	        case Types.LONGVARBINARY:
 	        case Types.VARBINARY:
 	        case Types.BINARY:
-	            newprop.setStringValue (rs.getString(rel.getDbField()));
+	            newprop.setStringValue (rs.getString(columns[i]));
 	            break;
 
 	        case Types.LONGVARCHAR:
 	        case Types.CHAR:
 	        case Types.VARCHAR:
 	        case Types.OTHER:
-	            newprop.setStringValue (rs.getString(rel.getDbField()));
+	            newprop.setStringValue (rs.getString(columns[i]));
 	            break;
 
 	        case Types.DATE:
 	        case Types.TIME:
 	        case Types.TIMESTAMP:
-	            newprop.setDateValue (rs.getTimestamp(rel.getDbField()));
+	            newprop.setDateValue (rs.getTimestamp(columns[i]));
 	            break;
 
 	        case Types.NULL:
@@ -333,7 +327,7 @@ public final class Node implements INode, Serializable {
 	            // continue;
 
 	        default:
-	            newprop.setStringValue (rs.getString(rel.getDbField()));
+	            newprop.setStringValue (rs.getString(columns[i]));
 	            break;
 	    }
 
@@ -478,16 +472,13 @@ public final class Node implements INode, Serializable {
     }
     
     /**
-     * Get something to identify this node within  a URL. This is the ID for anonymous nodes
+     * Get something to identify this node within a URL. This is the ID for anonymous nodes
      * and a property value for named properties.
      */
     public String getElementName () {
 	// if subnodes are also mounted as properties, try to get the "nice" prop value
 	// instead of the id by turning the anonymous flag off.
-	// Work around this for user objects to alsways return a URL like /users/username
-	if ("user".equalsIgnoreCase (prototype)) {
-	    anonymous = false;
-	} else if (parentHandle != null) {
+	if (parentHandle != null && lastNameCheck < Math.max (dbmap.getLastTypeChange(), lastmodified)) {
 	    try {
 	        Node p = parentHandle.getNode (nmgr);
 	        DbMapping parentmap = p.getDbMapping ();
@@ -508,8 +499,9 @@ public final class Node implements INode, Serializable {
 	    } catch (Exception ignore) {
 	        // just fall back to default method
 	    }
+	    lastNameCheck = System.currentTimeMillis ();
 	}
-    	return anonymous || name == null || name.length() == 0 ? id : name;
+	return anonymous || name == null || name.length() == 0 ? id : name;
     }
 
 
@@ -615,10 +607,13 @@ public final class Node implements INode, Serializable {
      * Register a node as parent of the present node. We can't refer to the node directly, so we use
      * the ID + DB map combo.
      */
-    public void setParent (Node parent) {
+    protected void setParent (Node parent) {
 	parentHandle = parent == null ? null : parent.getHandle ();
     }
 
+    /**
+     *  Set the parent handle which can be used to get the actual parent node.
+     */
     public void setParentHandle (NodeHandle parent)	{
 	parentHandle = parent;
     }
@@ -679,10 +674,11 @@ public final class Node implements INode, Serializable {
 
 	// check what's specified in the type.properties for this node.
 	ParentInfo[] parentInfo = null;
-	if (isRelational () && (lastParentSet < dbmap.getLastTypeChange() || lastParentSet < lastmodified))
+	if (isRelational () && lastParentSet < Math.max (dbmap.getLastTypeChange(), lastmodified))
 	    parentInfo = dbmap.getParentInfo ();
 
-	// check if current parent candidate matches presciption, if not, try to get it
+	// check if current parent candidate matches presciption,
+	// if not, try to get one that does.
 	if (parentInfo != null && state != TRANSIENT) {
 	    for (int i=0; i<parentInfo.length; i++) {
 	        ParentInfo pinfo = parentInfo[i];
@@ -693,7 +689,7 @@ public final class Node implements INode, Serializable {
 	        if (rel != null && rel.reftype == Relation.REFERENCE)
 	            pn = getNode (pinfo.propname, false);
 	        // the parent of this node is the app's root node...
-	        if (pinfo.isroot && pn == null)
+	        if (pn == null && pinfo.isroot)
 	            pn = nmgr.getNode ("0", nmgr.getDbMapping ("root"));
 	        // if we found a parent node, check if we ought to use a virtual or groupby node as parent
 	        if (pn != null) {
@@ -1092,11 +1088,6 @@ public final class Node implements INode, Serializable {
 	// which needs to be unset
 	if (dbmap != null) {
 	    Relation srel = dbmap.getSubnodeRelation ();
-	    /*if (srel != null && srel.reftype == Relation.BACKWARD) {
-	        Relation backlink = srel.otherType.columnNameToRelation (srel.getRemoteField ());
-	        if (backlink != null && id.equals (node.getString (backlink.propName, false)))
-	            node.unset (backlink.propName);
-	    } */
 	}
 
 	// check if subnodes are also accessed as properties. If so, also unset the property
@@ -1349,27 +1340,33 @@ public final class Node implements INode, Serializable {
 	    prop.convertToNodeReference (pmap);
 	}
 
-	// the property does not exist in our propmap - see if we can create it on the fly,
-	// either because it is mapped from a relational database or defined as virtual node
+	// the property does not exist in our propmap - see if we should create it on the fly,
+	// either because it is mapped to an object from relational database or defined as 
+	// collection aka virtual node
 	if (prop == null && dbmap != null) {
-	    Relation prel =  dbmap.getPropertyRelation (propname);
-	    Relation srel = dbmap.getSubnodeRelation ();
-	    if (prel == null && srel != null && srel.groupby != null)
-	        prel = srel;
-	    if (prel == null)
-	        prel = dbmap.getPropertyRelation ();
-	    if (prel != null) {
-	        // if what we want is a virtual node, fetch anyway.
-	        if (state == TRANSIENT && prel.virtual) {
-	            INode node = new Node (propname, prel.getPrototype (), nmgr);
-	            node.setDbMapping (prel.getVirtualMapping ());
+	    Relation propRel =  dbmap.getPropertyRelation (propname);
+	    // if no property relation is defined for this specific property name, 
+	    // use the generic property relation, if one is defined.
+	    if (propRel == null)
+	        propRel = dbmap.getPropertyRelation ();
+	    // so if we have a property relation and it does in fact link to another object...
+	    if (propRel != null && propRel.isCollection ()) {
+	        // in some cases we just want to create and set a generic node without consulting
+	        // the NodeManager if it exists: When we get a collection (aka virtual node)
+	        // from a transient node for the first time, or when we get a collection whose
+	        // content objects are stored in the embedded XML data storage.
+	        if (state == TRANSIENT && propRel.virtual) {
+	            INode node = new Node (propname, propRel.getPrototype (), nmgr);
+	            node.setDbMapping (propRel.getVirtualMapping ());
 	            setNode (propname, node);
 	            prop = (Property) propMap.get (propname);
-	        // if this is from relational database only fetch if this node is itself persistent.
-	        } else if (state != TRANSIENT && (prel.virtual || prel.accessor != null || prel.groupby != null)) {
+	        }
+	        // if this is from relational database only fetch if this node
+	        // is itself persistent.
+	        else if (state != TRANSIENT && propRel.createPropertyOnDemand ()) {
 	            // this may be a relational node stored by property name
 	            try {
-	                Node pn = nmgr.getNode (this, propname, prel);
+	                Node pn = nmgr.getNode (this, propname, propRel);
 	                if (pn != null) {
 	                    if (pn.parentHandle == null && !"root".equalsIgnoreCase (pn.getPrototype ())) {
 	                        pn.setParent (this);
@@ -1384,18 +1381,13 @@ public final class Node implements INode, Serializable {
 	        }
 	    }
 	}
-	
+
 	if (prop == null && inherit && getParent () != null && state != TRANSIENT) {
 	    prop = ((Node) getParent ()).getProperty (propname, inherit);
 	}
 	return prop;
     }
 
-    /* public String getString (String propname, String defaultValue, boolean inherit) {
-	String propValue = getString (propname, inherit);
-	return propValue == null ? defaultValue : propValue;
-    } */
-
     public String getString (String propname, boolean inherit) {  
 	// propname = propname.toLowerCase ();
 	Property prop = getProperty (propname, inherit);
@@ -1493,10 +1485,10 @@ public final class Node implements INode, Serializable {
 	    // check if this node is already registered with the old name; if so, remove it.
 	    // then set parent's property to this node for the new name value
 	    DbMapping parentmap = parent.getDbMapping ();
-	    Relation prel = parentmap.getPropertyRelation ();
+	    Relation propRel = parentmap.getPropertyRelation ();
 	    String dbcolumn = dbmap.propertyToColumnName (propname);
 
-	    if (prel != null && prel.accessor != null && prel.accessor.equals (dbcolumn)) {
+	    if (propRel != null && propRel.accessor != null && propRel.accessor.equals (dbcolumn)) {
 	        INode n = parent.getNode (value, false);
 	        if (n != null && n != this) {
 	            parent.unset (value);
diff --git a/src/helma/objectmodel/db/NodeHandle.java b/src/helma/objectmodel/db/NodeHandle.java
index 3908d0e3..297126f6 100644
--- a/src/helma/objectmodel/db/NodeHandle.java
+++ b/src/helma/objectmodel/db/NodeHandle.java
@@ -25,9 +25,6 @@ public final class NodeHandle implements INodeState, Serializable {
     // the node's key
     private Key key;
 
-    // cached DbMapping
-    private transient DbMapping dbmap;
-
     static final long serialVersionUID = 3067763116576910931L;
 
     /**
@@ -64,7 +61,8 @@ public final class NodeHandle implements INodeState, Serializable {
     }
 
     /**
-     *  Get the key for the node described by this handle. This may only be called on persistent Nodes.
+     *  Get the key for the node described by this handle. 
+     *  This may only be called on persistent Nodes.
      */
     public Key getKey () {
 	if (key == null)
@@ -73,7 +71,8 @@ public final class NodeHandle implements INodeState, Serializable {
     }
 
     /**
-     *  Get the ID for the node described by this handle. This may only be called on persistent Nodes.
+     *  Get the ID for the node described by this handle. 
+     *  This may only be called on persistent Nodes.
      */
     public String getID () {
 	if (key == null)
diff --git a/src/helma/objectmodel/db/NodeManager.java b/src/helma/objectmodel/db/NodeManager.java
index 5a485f02..c0852a3d 100644
--- a/src/helma/objectmodel/db/NodeManager.java
+++ b/src/helma/objectmodel/db/NodeManager.java
@@ -254,7 +254,7 @@ public final class NodeManager {
 	    // if a key for a node from within the DB
 	    // FIXME: This should never apply, since for every relation-based loading Synthetic Keys are used. Right?
 	    key = new DbKey (rel.otherType, kstr);
-	
+
 	// See if Transactor has already come across this node
 	Node node = tx.getVisitedNode (key);
 
@@ -1067,10 +1067,11 @@ public final class NodeManager {
     private Node getNodeByRelation (ITransaction txn, Node home, String kstr, Relation rel) throws Exception {
 	Node node = null;
 
-	if (rel.virtual) {
-
-	    node = new Node (home, kstr, safe, rel.prototype);
-	
+	if (rel != null && rel.virtual) {
+	    if (rel.needsPersistence ())
+	        node = (Node) home.createNode (kstr);
+	    else
+	        node = new Node (home, kstr, safe, rel.prototype);
 	    if (rel.prototype != null) {
 	        node.setPrototype (rel.prototype);
 	        node.setDbMapping (app.getDbMapping (rel.prototype));
diff --git a/src/helma/objectmodel/db/Relation.java b/src/helma/objectmodel/db/Relation.java
index 035401fa..94da5a86 100644
--- a/src/helma/objectmodel/db/Relation.java
+++ b/src/helma/objectmodel/db/Relation.java
@@ -57,14 +57,13 @@ public final class Relation {
 
     String accessor; // db column used to access objects through this relation
     String order;
-    String groupbyorder;
+    String groupbyOrder;
     String groupby;
     String prototype;
-    String groupbyprototype;
+    String groupbyPrototype;
     String filter;
     int maxSize = 0;
 
-    // Relation subnoderelation = null; // additional relation used to filter subnodes for virtual nodes
 
     /**
      * This constructor makes a copy of an existing relation. Not all fields are copied, just those
@@ -156,8 +155,8 @@ public final class Relation {
 	    // FIXME: needs to be synchronized?
 	     if (virtualMapping != null) {
 	        virtualMapping.lastTypeChange = ownType.lastTypeChange;
-	        virtualMapping.subnodesRel = getVirtualSubnodeRelation ();
-	        virtualMapping.propertiesRel = getVirtualPropertyRelation ();
+	        virtualMapping.subRelation = getVirtualSubnodeRelation ();
+	        virtualMapping.propRelation = getVirtualPropertyRelation ();
 	    }
 	}
     }
@@ -190,12 +189,12 @@ public final class Relation {
 	if (groupby != null && groupby.trim().length() == 0)
 	    groupby = null;
 	if (groupby != null) {
-	    groupbyorder = props.getProperty (propName+".group.order");
-	    if (groupbyorder != null && groupbyorder.trim().length() == 0)
-	        groupbyorder = null;
-	    groupbyprototype = props.getProperty (propName+".group.prototype");
-	    if (groupbyprototype != null && groupbyprototype.trim().length() == 0)
-	        groupbyprototype = null;
+	    groupbyOrder = props.getProperty (propName+".group.order");
+	    if (groupbyOrder != null && groupbyOrder.trim().length() == 0)
+	        groupbyOrder = null;
+	    groupbyPrototype = props.getProperty (propName+".group.prototype");
+	    if (groupbyPrototype != null && groupbyPrototype.trim().length() == 0)
+	        groupbyPrototype = null;
 	    // aggressive loading and caching is not supported for groupby-nodes
 	    aggressiveLoading = aggressiveCaching = false;
 	}
@@ -228,7 +227,56 @@ public final class Relation {
     public boolean isPrimitive () {
 	return reftype == PRIMITIVE;
     }
-    
+
+    /**
+     *  Returns true if this Relation describes an object reference property
+     */
+    public boolean isReference () {
+	return reftype == REFERENCE;
+    }
+
+    /**
+     *  Returns true if this Relation describes a collection object property
+     */
+    public boolean isCollection () {
+	return reftype == COLLECTION;
+    }
+
+    /**
+     *  Tell wether the property described by this relation is to be handled as private, i.e.
+     *  a change on it should not result in any changed object/collection relations.
+     */
+    public boolean isPrivate () {
+	return isPrivate;
+    }
+
+    /**
+     *  Returns true if the object represented by this Relation has to be
+     *  created dynamically by the Helma objectmodel runtime as a virtual
+     *  node. Virtual nodes are objects which are only generated on demand
+     *  and never stored to a persistent storage.
+     */
+    public boolean createPropertyOnDemand () {
+	return virtual || accessor != null || groupby != null;
+    }
+
+    /**
+     *  Returns true if the object represented by this Relation has to be
+     *  persisted in the internal db in order to be functional. This is true if
+     *  the subnodes contained in this collection are stored in the embedded
+     *  database. In this case, the collection itself must also be an ordinary
+     *  object stored in the db, since a virtual collection would lose its
+     *  its content after restarts.
+     */
+    public boolean needsPersistence () {
+	if (!virtual)
+	    return false;
+	if (prototype == null)
+	    return !otherType.isRelational ();
+	DbMapping sub = otherType.getSubnodeMapping ();
+	return sub != null && !sub.isRelational ();
+    }
+
     /**
      * Return the prototype to be used for object reached by this relation
      */
@@ -301,8 +349,8 @@ public final class Relation {
 	    return null;
 	if (virtualMapping == null) {
 	    virtualMapping = new DbMapping (ownType.app);
-	    virtualMapping.subnodesRel = getVirtualSubnodeRelation ();
-	    virtualMapping.propertiesRel = getVirtualPropertyRelation ();
+	    virtualMapping.subRelation = getVirtualSubnodeRelation ();
+	    virtualMapping.propRelation = getVirtualPropertyRelation ();
 	}
 	return virtualMapping;
     }
@@ -316,8 +364,8 @@ public final class Relation {
 	    throw new RuntimeException ("getVirtualSubnodeRelation called on non-virtual relation");
 	Relation vr = new Relation (this);
 	vr.groupby = groupby;
-	vr.groupbyorder = groupbyorder;
-	vr.groupbyprototype = groupbyprototype;
+	vr.groupbyOrder = groupbyOrder;
+	vr.groupbyPrototype = groupbyPrototype;
 	vr.order = order;
 	vr.filter = filter;
 	vr.maxSize = maxSize;
@@ -335,8 +383,8 @@ public final class Relation {
 	    throw new RuntimeException ("getVirtualPropertyRelation called on non-virtual relation");
 	Relation vr = new Relation (this);
 	vr.groupby = groupby;
-	vr.groupbyorder = groupbyorder;
-	vr.groupbyprototype = groupbyprototype;
+	vr.groupbyOrder = groupbyOrder;
+	vr.groupbyPrototype = groupbyPrototype;
 	vr.order = order;
 	vr.filter = filter;
 	vr.maxSize = maxSize;
@@ -352,7 +400,7 @@ public final class Relation {
 	    throw new RuntimeException ("getGroupbySubnodeRelation called on non-group-by relation");
 	Relation vr = new Relation (this);
 	vr.order = order;
-	vr.prototype = groupbyprototype;
+	vr.prototype = groupbyPrototype;
 	vr.filter = filter;
 	vr.constraints = constraints;
 	vr.addConstraint (new Constraint (null, null, groupby, true));
@@ -369,7 +417,7 @@ public final class Relation {
 	    throw new RuntimeException ("getGroupbyPropertyRelation called on non-group-by relation");
 	Relation vr = new Relation (this);
 	vr.order = order;
-	vr.prototype = groupbyprototype;
+	vr.prototype = groupbyPrototype;
 	vr.filter = filter;
 	vr.constraints = constraints;
 	vr.addConstraint (new Constraint (null, null, groupby, true));
@@ -410,8 +458,8 @@ public final class Relation {
 	}
 	if (groupby != null) {
 	    q.append (" GROUP BY "+groupby);
-	    if (useOrder && groupbyorder != null)
-	        q.append (" ORDER BY "+groupbyorder);
+	    if (useOrder && groupbyOrder != null)
+	        q.append (" ORDER BY "+groupbyOrder);
 	} else if (useOrder && order != null)
 	    q.append (" ORDER BY "+order);
 	return q.toString ();
@@ -437,26 +485,19 @@ public final class Relation {
      */
     public String getOrder () {
 	if (groupby != null)
-	    return groupbyorder;
+	    return groupbyOrder;
 	else
 	    return order;
     }
 
     /**
-     *  Tell wether the property described by this relation is to be handled as readonly/write protected.
+     *  Tell wether the property described by this relation is to be handled
+     *  as readonly/write protected.
      */
     public boolean isReadonly () {
 	return readonly;
     }
 
-    /**
-     *  Tell wether the property described by this relation is to be handled as private, i.e.
-     *  a change on it should not result in any changed object/collection relations.
-     */
-    public boolean isPrivate () {
-	return isPrivate;
-    }
-
 
     /**
      * Check if the child node fullfills the constraints defined by this relation.