Importing RDB’s to C++/Java
If the RDB is imported to an object-relational database implemented in C++ or Java, then during import the fkey fields of RDB tuple types should be converted to corresponding C++/Java object reference types.
Caveat/pre-condition: All fkeys implied by links on the RDB’s data model or EERD must conform to inheritance and type constraints of the language (C++ or Java).
Fkeys in an RDB can also support non-exhaustive or over-lapping subclasses (going beyond C++ constraints).
Fkeys and object references can also support dynamic migration (of an object among the subclasses of its class).
- Example: An object may make transitions among OLC states (states become subclasses of the object’s class).