The best approach for mapping is up to each project and product vendor. The following table identifies and describes levels of object-relational mapping sophistication from simply using the relational model up to implementing a full object mapping as described in this document. At the end is a short description of the functional capabilities of an active object server. 1 Pure Relational Use relational database model in the client and the server. The client UI is organized around rows and tables and uses the standard relational operations to tables and rows.
Convert rows from the database into basic objects on the client.
3 Medium Object Mapping Primarily use objects on the client and write the entire application behavior in terms of these objects. Application may have to manage transactions of these objects. Flexibly convert rows from the database into the appropriate type of objects and maintain identity for these objects. Manage associations between objects of variable types. Allow retrieval queries to be specified in object model terms and then converted to the needed SQL calls.