Persistence, EJBs and OO-Relational mapping

I read many articles on persistence recently, but all of them leave me more confused than I intitially was.

First let me state the main issue. What is the rationale behind trying to persist "relational data" in the form of "object oriented data"?

As every one here knows, a well designed relational data model is more than the data itself. The relational tables are managed with referential integrity rules, triggers and constraints. Above all, the relational data posesses rigorous relational arithmatic properties like "orthogonality" and "closure".

At the best, the OO paradigm can only implemet the relationships, but may not extend to cover other properties of relational databases mentioned above. Or am I wrong?

No one has problems with the 3-tier or n-tier application architecture models, then, why are we trying to bring the data layer into middleware tier? Isn't it too simplistic to ignore the power, flexibility and ubiquity of the RDBMSs?

OO technology is great. Awesome design patterns are direct results of this wonderful technology. Concepts like composition, interfaces, serialization, polymorphism etc. are all great. Right way to use these techniques is in solving the business processes, business rules and application architecture, but not modeling the data into the middle tier.

Or am I completely wrong? Can somebody explain me where the technology of EJB and OO-Relational mapping are leading us towards?

-S

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Before you buy. Received on Wed Dec 06 2000 - 21:05:15 CET