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

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






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


> Robert Martin wrote:




>> On 2006-05-31 12:44:04 -0500, "Marshall" <marshall.spight_at_gmail.com> 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.


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Received on Tue Jun 13 2006 - 13:35:34 CEST












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