Re: The wisdom of the object mentors (Was: Searching OO Associations with RDBMS Persistence Models)

From: Robert Martin <>
Date: Tue, 13 Jun 2006 13:35:34 +0200
Message-ID: <2006061313353443042-unclebob_at_objectmentorcom>

On 2006-06-02 09:06:56 +0200, "Marshall" <> said:

> Robert Martin wrote:

>> On 2006-05-31 12:44:04 -0500, "Marshall" <> said:
>>> Wow, I missed that one completely. "Isolate the data management
>>> mechanism from the data model." How in tarnation is the data
>>> manager doing to manage the data if it is isolated from the
>>> data model?

>> It's called decoupling. Generally it's based on dynamic polymorphism
>> which is a lot of syllables that really mean function pointers. The
>> idea is that you write the application program in such a way that it
>> can manipulate the data in the data model without coupling it directly
>> to the DBMS, or the details of the schema. The decoupling mechanism is
>> very similar to the mechanism used to create device independence in
>> operating systems like Unix.
> That's a complete non-sequitur from the sentence I took issue with.
> You said, "Isolate the data management mechanism from the data
> model." This has a very clear denotation: it means the dbms should
> not know the schema of the data it is managing. This is clearly
> self-contradictory. Perhaps you didn't mean that? Perhaps the
> later "it's called decoupling" paragraph is more like what you
> really meant to say?

Yes, I think we have a vocabulary problem. Sorry. What I want to separate is the application code, and it's internal data models, from the DBMS and the schema.

Robert C. Martin (Uncle Bob)  | email:
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Received on Tue Jun 13 2006 - 13:35:34 CEST

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