Re: foundations of relational theory?

"Marshall Spight" <mspight_at_dnai.com> wrote:

>"Tony Gravagno" wrote
>> Also,
>> relational people want the DBMS to maintain referential integrity,
>> while Pick people assume that's the responsibility of the app
>> developer - neither view is "right" in terms long-lasting, quality
>> solutions, they're just different.
>
>There are specific practical benefits to enforcing integrity
>in the DBMS vs. enforcing them in the various applications.
>It's not a question of preferences.
>Marshall

There is no disagreement here. If an order-detail record refers to an inventory part then it's critical that the inventory file not be purged of referenced parts. This can happen in a poorly coded MV application but should not happen with a properly configured relational schema. Note the words "can" and "should". A relational DBA can make the same mistake of improper definition as a MV coder can in his app code. In both cases the error would be caught and fixed immediately.

Granted, the possibility for error is increased if an MV developer has multiple entry points into the app for database manipulation. But a properly designed app doesn't have a multitude of entry points for maintaining the same data, update routines should be consolidated into a manageable number of entry points, and all programs should use the same routines. Again we come to the point where proper maintenance of the database becomes the responsibility of the application developer and his/her understanding of proper design - this is independent of the database model. Neither model guarantees success, each model is subject to the understanding of those who implement it, so I'll maintain that neither view is right, but given a proper implementation both views are just as valid in this respect - neither view is wrong, they're just different and deserve equal understanding.

Tony Received on Tue Oct 28 2003 - 03:53:05 CET