diff --git a/src/helma/framework/core/Application.java b/src/helma/framework/core/Application.java
index aaadc145..f61bf1c3 100644
--- a/src/helma/framework/core/Application.java
+++ b/src/helma/framework/core/Application.java
@@ -74,7 +74,6 @@ public final class Application
     long starttime;
 
     Hashtable sessions;
-    Hashtable dbMappings;
     Hashtable dbSources;
 
     // internal worker thread for scheduler, session cleanup etc.
@@ -224,7 +223,6 @@ public final class Application
 	}
 
 	sessions = new Hashtable ();
-	dbMappings = new Hashtable ();
 	dbSources = new Hashtable ();
 
 	cachenode = new TransientNode ("app");
@@ -281,8 +279,7 @@ public final class Application
 	p.put ("_children", "collection(user)");
 	p.put ("_children.accessname", usernameField);
 	userRootMapping = new DbMapping (this, "__userroot__", p);
-
-	rewireDbMappings ();
+	userRootMapping.update ();
 
 	nmgr = new NodeManager (this, dbDir.getAbsolutePath (), props);
 
@@ -1144,39 +1141,6 @@ public final class Application
 	logEvent ("Scheduler for "+name+" exiting");
     }
 
-    /**
-     *  This method is called after the type.properties files are read on all prototypes, or after one
-     * or more of the type properties have been re-read after an update, to let the DbMappings reestablish
-     * the relations among them according to their mappings.
-     */
-    public void rewireDbMappings () {
-	for (Enumeration e=dbMappings.elements(); e.hasMoreElements(); ) {
-	    try {
-	        DbMapping m = (DbMapping) e.nextElement ();
-	        m.rewire ();
-	        String typename = m.getTypeName ();
-	        // set prototype hierarchy
-	        if (!"hopobject".equalsIgnoreCase (typename) && !"global".equalsIgnoreCase (typename)) {
-	            Prototype proto = (Prototype) typemgr.prototypes.get (typename);
-	            if (proto != null) {
-	                String protoname = m.getExtends ();
-	                // only use hopobject prototype if we're scripting HopObjects, not
-	                // java objects.
-	                boolean isjava = isJavaPrototype (typename);
-	                if (protoname == null && !isjava)
-	                    protoname = "hopobject";
-	                Prototype parentProto = (Prototype) typemgr.prototypes.get (protoname);
-	                if (parentProto == null && !isjava)
-	                    parentProto = (Prototype) typemgr.prototypes.get ("hopobject");
-	                if (parentProto != null)
-	                    proto.setParentPrototype (parentProto);
-	            }
-	        }
-	    } catch (Exception x) {
-	        logEvent ("Error rewiring DbMappings: "+x);
-	    }
-	}
-    }
 
     /**
      * Check whether a prototype is for scripting a java class, i.e. if there's an entry
@@ -1230,15 +1194,13 @@ public final class Application
      * Get the DbMapping associated with a prototype name in this application
      */
     public DbMapping getDbMapping (String typename) {
-	return typename == null ? null : (DbMapping) dbMappings.get (typename);
+	Prototype proto = typemgr.getPrototype (typename);
+	if (proto == null)
+	    return null;
+	return proto.getDbMapping ();
     }
 
-    /**
-     * Associate a DbMapping object with a prototype name for this application.
-     */
-    public void putDbMapping (String typename, DbMapping dbmap) {
-	dbMappings.put (typename, dbmap);
-    }
+
     /**
      * Proxy method to get a property from the applications properties.
      */
diff --git a/src/helma/framework/core/Prototype.java b/src/helma/framework/core/Prototype.java
index ec5f259a..b26b112d 100644
--- a/src/helma/framework/core/Prototype.java
+++ b/src/helma/framework/core/Prototype.java
@@ -10,13 +10,14 @@ import java.io.*;
 import helma.framework.*;
 import helma.scripting.*;
 import helma.objectmodel.*;
+import helma.objectmodel.db.DbMapping;
 import helma.util.Updatable;
 
 
 /**
  * The Prototype class represents Script prototypes/type defined in a Helma
- * application. This class manages a prototypes templates, functions and actions 
- * as well as optional information about the mapping of this type to a 
+ * application. This class manages a prototypes templates, functions and actions
+ * as well as optional information about the mapping of this type to a
  * relational database table.
  */
 
@@ -32,6 +33,8 @@ public final class Prototype {
     final HashMap skins;
     final HashMap updatables;
     
+    DbMapping dbmap;
+
     // lastCheck is the time the prototype's files were last checked
     private long lastCheck;
     // lastUpdate is the time at which any of the prototype's files were
@@ -68,7 +71,7 @@ public final class Prototype {
 
 
     /**
-     *  Set the parent prototype of this prototype, i.e. the prototype this 
+     *  Set the parent prototype of this prototype, i.e. the prototype this
      *  prototype inherits from.
      */
     public void setParentPrototype (Prototype parent) {
@@ -86,6 +89,14 @@ public final class Prototype {
 	return parent;
     }
 
+    public void setDbMapping (DbMapping dbmap) {
+	this.dbmap = dbmap;
+    }
+    
+    public DbMapping getDbMapping () {
+	return dbmap;
+    }
+
     /**
      *  Get a template defined for this prototype. Templates
      *  are files that mix layout and code and were used
diff --git a/src/helma/framework/core/TypeManager.java b/src/helma/framework/core/TypeManager.java
index de2faa6e..d7021ef5 100644
--- a/src/helma/framework/core/TypeManager.java
+++ b/src/helma/framework/core/TypeManager.java
@@ -23,7 +23,7 @@ public final class TypeManager {
     HashMap prototypes;
     HashMap zipfiles;
     long lastCheck = 0;
-    boolean rewire;
+    // boolean rewire;
 
     final static String[] standardTypes = {"user", "global", "root", "hopobject"};
     final static String templateExtension = ".hsp";
@@ -54,6 +54,7 @@ public final class TypeManager {
      * compile or evaluate any scripts.
      */
     public void createPrototypes () {
+        // loop through directories and create prototypes
         checkFiles ();
         // check if standard prototypes have been created
         // if not, create them.
@@ -62,9 +63,22 @@ public final class TypeManager {
             if (prototypes.get (pname) == null) {
                 Prototype proto = new Prototype (pname, app);
                 registerPrototype (pname, new File (appDir, pname), proto);
-                prototypes.put (pname, proto);
             }
         }
+        Prototype hobjectProto = getPrototype ("hopobject");
+        // loop through freshly created prototypes and rewire them,
+        // i.e. establish connections between them (inherit, collection etc.)
+        for (Iterator i = prototypes.values().iterator(); i.hasNext(); ) {
+            Prototype proto = (Prototype) i.next();
+            DbMapping dbm = proto.getDbMapping ();
+            dbm.update ();
+            // set parent prototype
+            String parentName = dbm.getExtends ();
+            if (parentName == null)
+                proto.setParentPrototype (hobjectProto);
+            else
+                proto.setParentPrototype (getPrototype (parentName));
+        }
     }
 
 
@@ -82,34 +96,44 @@ public final class TypeManager {
     }
 
     /**
-     * Run through application's prototype directories and check if anything has been updated.
+     * Run through application's prototype directories and check if
+     * there are any prototypes to be created.
      */
     public void checkFiles () {
 	// long now = System.currentTimeMillis ();
-	// System.out.print ("checking "+Thread.currentThread ());
+	// System.out.print ("checking prototypes for  "+app);
 	File[] list = appDir.listFiles ();
 	if (list == null)
 	    throw new RuntimeException ("Can't read app directory "+appDir+" - check permissions");
 	for (int i=0; i<list.length; i++) {
 	    String filename = list[i].getName ();
 	    Prototype proto = getPrototype (filename);
-	    if (proto != null) {
-	        // check if existing prototype needs update
-	        // app.logEvent (protoDir.lastModified ());
-	        // updatePrototype (filename, list[i], proto);
-	    } else if (list[i].isDirectory () && isValidTypeName (filename)) {
+	    // if prototype doesn't exist, create it
+	    if (proto == null) {
 	        // leave out ".." and other directories that contain "."
-	        // create new prototype
-	        proto = new Prototype (filename, app);
-	        registerPrototype (filename, list[i], proto);
-	        prototypes.put (filename, proto);
-	        // give logger thread a chance to tell what's going on
-	        // Thread.yield();
-	    } else if (filename.toLowerCase().endsWith (".zip") && !list[i].isDirectory ()) {
-	        ZippedAppFile zipped = (ZippedAppFile) zipfiles.get (filename);
-	        if (zipped == null) {
-	            zipped = new ZippedAppFile (list[i], app);
-	            zipfiles.put (filename, zipped);
+	        if (list[i].isDirectory () && isValidTypeName (filename)) {
+	            // create new prototype
+	            proto = new Prototype (filename, app);
+	            registerPrototype (filename, list[i], proto);
+	            // give logger thread a chance to tell what's going on
+	            // Thread.yield();
+	        } else if (filename.toLowerCase().endsWith (".zip") && !list[i].isDirectory ()) {
+	            ZippedAppFile zipped = (ZippedAppFile) zipfiles.get (filename);
+	            if (zipped == null) {
+	                zipped = new ZippedAppFile (list[i], app);
+	                zipfiles.put (filename, zipped);
+	            }
+	        }
+	    } else {
+	        // update prototype's type mapping
+	        DbMapping dbmap = proto.getDbMapping ();
+	        if (dbmap != null && dbmap.needsUpdate ()) {
+	            dbmap.update ();
+	        // set parent prototype, in case it has changed.
+	        String parentName = dbmap.getExtends ();
+	        if (parentName == null)
+	            parentName = "hopobject";
+	        proto.setParentPrototype (getPrototype (parentName));
 	        }
 	    }
 	}
@@ -122,11 +146,6 @@ public final class TypeManager {
 	    }
 	}
 
-	if (rewire) {
-	    // there have been changes in the  DbMappings
-	    app.rewireDbMappings ();
-	    rewire = false;
-	}
     }
 
 
@@ -148,7 +167,9 @@ public final class TypeManager {
     }
 
     /**
-     * Get a prototype, creating it if id doesn't already exist
+     * Get a prototype, creating it if it doesn't already exist. Note
+     * that it doesn't create a DbMapping - this is left to the 
+     * caller (e.g. ZippedAppFile).
      */
     public Prototype createPrototype (String typename) {
 	Prototype p = getPrototype (typename);
@@ -171,9 +192,13 @@ public final class TypeManager {
         File propfile = new File (dir, "type.properties");
         SystemProperties props = new SystemProperties (propfile.getAbsolutePath ());
         DbMapping dbmap = new DbMapping (app, name, props);
-        proto.updatables.put ("type.properties", dbmap);
+        // we don't need to put the DbMapping into proto.updatables, because
+        // dbmappings are checked separately in checkFiles for each request
+        // proto.updatables.put ("type.properties", dbmap);
+        proto.setDbMapping (dbmap);
 
-        // app.scriptingEngine.updatePrototype (proto);
+        // put the prototype into our map
+        prototypes.put (name, proto);
     }
 
 
@@ -226,8 +251,8 @@ public final class TypeManager {
                 String fn = list[i];
                 if (!proto.updatables.containsKey (fn)) {
                     if (fn.endsWith (templateExtension) || fn.endsWith (scriptExtension) ||
-	    	fn.endsWith (actionExtension) || fn.endsWith (skinExtension) ||
-	    	"type.properties".equalsIgnoreCase (fn)) {
+			fn.endsWith (actionExtension) || fn.endsWith (skinExtension) ||
+			"type.properties".equalsIgnoreCase (fn)) {
                         needsUpdate = true;
                         // updatables.add ("[new:"+proto.getName()+"/"+fn+"]");
                     }
@@ -299,17 +324,13 @@ public final class TypeManager {
             for (Iterator i = updatables.iterator(); i.hasNext(); ) {
                 Updatable upd = (Updatable) i.next();
 
-                if (upd.needsUpdate ()) {
-                    if (upd instanceof DbMapping)
-                        rewire = true;
-                    try {
-                        upd.update ();
-                    } catch (Exception x) {
-                         if (upd instanceof DbMapping)
-                            app.logEvent ("Error updating db mapping for type "+proto.getName()+": "+x);
-                         else
-                            app.logEvent ("Error updating "+upd+" of prototye type "+proto.getName()+": "+x);
-                    }
+                try {
+                    upd.update ();
+                } catch (Exception x) {
+                     if (upd instanceof DbMapping)
+                        app.logEvent ("Error updating db mapping for type "+proto.getName()+": "+x);
+                     else
+                        app.logEvent ("Error updating "+upd+" of prototye type "+proto.getName()+": "+x);
                 }
             }
         }
diff --git a/src/helma/framework/core/ZippedAppFile.java b/src/helma/framework/core/ZippedAppFile.java
index 9ccf5fef..c7ad03b1 100644
--- a/src/helma/framework/core/ZippedAppFile.java
+++ b/src/helma/framework/core/ZippedAppFile.java
@@ -118,7 +118,7 @@ public class ZippedAppFile implements Updatable {
 	                // DbMapping doesn't exist, we still need to create one
 	                SystemProperties props = new SystemProperties ();
 	                // DbMapping does its own registering, just construct it.
-	                new DbMapping (app, proto.getName (), props);
+	                proto.setDbMapping (new DbMapping (app, proto.getName (), props));
 	            }
 	        }
 	    } catch (Throwable x) {
diff --git a/src/helma/objectmodel/db/DbMapping.java b/src/helma/objectmodel/db/DbMapping.java
index 543bf6c7..873b8679 100644
--- a/src/helma/objectmodel/db/DbMapping.java
+++ b/src/helma/objectmodel/db/DbMapping.java
@@ -119,9 +119,6 @@ public final class DbMapping implements Updatable {
 	idField = null;
 
 	this.props = props;
-	update ();
-
-	app.putDbMapping (typename, this);
     }
 
     /**
@@ -139,13 +136,6 @@ public final class DbMapping implements Updatable {
      */
     public synchronized void update () {
 
-	// determin file format version of type.properties file
-	/* String versionInfo = props.getProperty ("_version");
-	if ("1.2".equals (versionInfo))
-	    version = 1;
-	else
-	    version = 0; */
-
 	table = props.getProperty ("_table");
 	idgen = props.getProperty ("_idgen");
 	// see if there is a field which specifies the prototype of objects, if different prototypes
@@ -170,32 +160,27 @@ public final class DbMapping implements Updatable {
 	nameField = props.getProperty ("_name");
 
 	protoField = props.getProperty ("_prototype");
-	
-	String parentMapping = props.getProperty ("_parent");
-	if (parentMapping != null) {
+
+	String parentSpec = props.getProperty ("_parent");
+	if (parentSpec != null) {
 	    // comma-separated list of properties to be used as parent
-	    StringTokenizer st = new StringTokenizer (parentMapping, ",;");
+	    StringTokenizer st = new StringTokenizer (parentSpec, ",;");
 	    parent = new ParentInfo[st.countTokens()];
 	    for (int i=0; i<parent.length; i++)
 	        parent[i] = new ParentInfo (st.nextToken().trim());
-	} else
+	} else {
 	    parent = null;
-	
+	}
+
 	lastTypeChange = props.lastModified ();
 	// set the cached schema & keydef to null so it's rebuilt the next time around
 	schema = null;
 	keydef = null;
-    }
 
-    /**
-     * This is the second part of the property reading process, called after the first part has been
-     * completed on all other mappings in this application
-     */
-    public synchronized void rewire () {
 	if (extendsProto != null) {
 	    parentMapping = app.getDbMapping (extendsProto);
 	}
-	
+
 	// if (table != null && source != null) {
 	// app.logEvent ("set data source for "+typename+" to "+source);
 	HashMap p2d = new HashMap ();
diff --git a/src/helma/objectmodel/db/NodeManager.java b/src/helma/objectmodel/db/NodeManager.java
index 8c285bf5..9fb91a3b 100644
--- a/src/helma/objectmodel/db/NodeManager.java
+++ b/src/helma/objectmodel/db/NodeManager.java
@@ -873,7 +873,7 @@ public final class NodeManager {
 	Node node = null;
 	DbMapping dbm = app.getDbMapping (key.getStorageName ());
 	String kstr = key.getID ();
-	
+
 	if (dbm == null || !dbm.isRelational ()) {
 	    node = (Node)db.getNode (txn, kstr);
 	    node.nmgr = safe;
@@ -881,7 +881,7 @@ public final class NodeManager {
 	        node.setDbMapping (dbm);
 	} else {
 	    String idfield =dbm.getIDField ();
-	
+
 	    TableDataSet tds = null;
 	    try {
 	        tds = new TableDataSet (dbm.getConnection (), dbm.getSchema (), dbm.getKeyDef ());
diff --git a/src/helma/objectmodel/db/Relation.java b/src/helma/objectmodel/db/Relation.java
index c3cc2780..4ec33af7 100644
--- a/src/helma/objectmodel/db/Relation.java
+++ b/src/helma/objectmodel/db/Relation.java
@@ -38,9 +38,6 @@ public final class Relation {
     //  if this relation defines a virtual node, we need to provide a DbMapping for these virtual nodes
     DbMapping virtualMapping;
 
-    Relation virtualRelation;
-    Relation groupRelation;
-
     String propName;
     String columnName;
 
@@ -150,6 +147,14 @@ public final class Relation {
 
 	    constraints = new Constraint[newConstraints.size()];
 	    newConstraints.copyInto (constraints);
+	    // if DbMapping for virtual nodes has already been created, 
+	    // update its subnode relation.
+	    // FIXME: needs to be synchronized?
+	     if (virtualMapping != null) {
+	        virtualMapping.lastTypeChange = ownType.lastTypeChange;
+	        virtualMapping.subnodesRel = getVirtualSubnodeRelation ();
+	        virtualMapping.propertiesRel = getVirtualPropertyRelation ();
+	    }
 	}
     }
 
@@ -301,6 +306,7 @@ public final class Relation {
 	vr.groupbyprototype = groupbyprototype;
 	vr.order = order;
 	vr.filter = filter;
+	vr.maxSize = maxSize;
 	vr.constraints = constraints;
 	vr.aggressiveLoading = aggressiveLoading;
 	vr.aggressiveCaching = aggressiveCaching;
@@ -319,6 +325,7 @@ public final class Relation {
 	vr.groupbyprototype = groupbyprototype;
 	vr.order = order;
 	vr.filter = filter;
+	vr.maxSize = maxSize;
 	vr.constraints = constraints;
 	return vr;
     }