Systems and techniques to derive virtual objects at run-time from persistencely stored objects. In general, in one implementation, the technique includes receiving a request for a target object from a requesting application. It is determined whether a delta link is associated with the target object. The delta link includes a location of the target object and information describing a desired difference between the target object and a derived object to be returned to the requesting application. The target object is located and a derived object is generated from the target object and the information in the delta link. The derived object is then returned to the requesting application. The target object, and derived object, may include a number of elements. The elements may be name-value pairs, or "properties", or a number of child objects in an object hierarchy.