A computer-implemented method and apparatus for retrieving over a network a subset of object data from a persistence layer. The persistence layer is structured at least partially upon an object model definition. A server computer receives over the network a request from a client computer for object persisted data stored in the persistence layer. The server computer parses the request to obtain search criteria and object association data, wherein the object association data identifies at least one association between a pair of objects. Filtering criteria is created based upon the parsed search criteria and object association data. The object model definition determines how the search criteria and the object association data form the filtering criteria. The object data from the persistence layer is filtered by the filtering criteria in order to generate the object data subset. The object data subset may also be encoded as a package of objects formatted as an Extensible Markup Language (XML) document. The server computer transmits the encoded object data subset to the client computer over the network.