1. A method for setting a new reference value for managing bi-directional relationships between objects in an object model, the method comprising the steps of: receiving bi-directional relationship information indicating interrelation between objects having one or more bi-directional relationships; creating proxy objects based on the bi-directional relationship information for selected bi-directional relationship objects having bi-directional relationships; receiving a new reference value to be set in a selected object relating to a bi-directional relationship; determining, using one or more of the proxy objects, a new peer value to be set for a peer object which has the bi-directional relationship with the selected object; and setting the new peer value to a proxy object created for the peer object.