Re: The wisdom of the object mentors (Was: Searching OO Associations with RDBMS Persistence Models)
Date: Fri, 02 Jun 2006 17:34:03 GMT
> A DBMS is not "storage." A DBMS is a system that manages
> data, where "manages" describes a whole host of high level
In the ideal situation, most changes in one module don't ripple into another. Coherent changes represent adding a feature to A such that B indeed upgrades to support its part of the feature. The change to B wasn't just adjusting to A's new feature; B gets more value.
An example of coupling: Table Q gets a new join, to Table J. Now I must go to the application code and start throwing away J records, because the data queries now get them. (I'm aware joins don't automatically do that; it's just an example.)
An example of coherency: Field Q:N was an integer, now it's a long. I must also change copies of N in the application. Both fields now have more value - they can store more numbers. So Q:N coheres with application variable N.
> The c.o. people's arguments are mostly based on the false
> premise that a DBMS is a kind of storage mechanism.
> Once you accept a false premise, you can prove anything.
-- PhlipReceived on Fri Jun 02 2006 - 19:34:03 CEST