ExtObjectContainer#descend method allows you to navigate from a persistent object to it's members without activating or instantiating intermediate objects.
01public static void testDescend(){ 02
storeSensorPanel(); 03
ObjectContainer db = Db4o.openFile(Util.YAPFILENAME); 04
try { 05
db.ext().configure().activationDepth(1); 06
System.out.println("Object container activation depth = 1"); 07
ObjectSet result = db.get(new SensorPanel(1)); 08
SensorPanel spParent = (SensorPanel)result.get(0); 09
SensorPanel spDescend = (SensorPanel)db.ext().descend((Object)spParent, new String[]{"next","next","next","next","next"}); 10
db.ext().activate(spDescend, 5); 11
System.out.println(spDescend); 12
} finally { 13
db.close(); 14
} 15
}
Navigating in this way can save you resources on activating only the objects you really need.