When you have inheritance hierarchies in your object model, they should be correctly modeled. We present below the three possible ways to map an inheritance hierarchy to the relational world, then we'll see how to model these so that they can be taken into account by the framework.
There are three typical ways to model an inheritance hierarchy into an RDBMS schema-we do not take into account special RDBMS functionalities, just raw relational/SQL possibilities. Among these three, only one, Horizontal Mapping, is supported by the framework so far.
A more complete discussion, along with figures and examples, can be found at http://www.objectmatter.com/,
A1) which stores the instance data. This configuration does not put any information about the inheritance schema into the relational database, rather it lets the runtime do the job and take the inheritance into account.
1stored in the table's column
'TYPE', while instances of class A2 will map to rows whose type is
ZModelizationToolor directly in an xml-model and used by the framework's core, is not a model per se but rather a mapping of an object model to a relational model. As a consequence, you should not be surprised that, whatever mapping you choose to model a specific inheritance hierarchy, each entity and all sub-entities must define and describe all entity attributes and relationships-inherited or not.