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

From: Cimode <cimode_at_hotmail.com>
Date: 1 Jun 2006 12:06:40 -0700
Message-ID: <1149188800.056087.159770_at_h76g2000cwa.googlegroups.com>


Thank you for your feedback...

<<This is urban myth. SQL is widely criticised for its NULL and duplicate
treatment. There is several more little annoying inconsistencies. >> "myth" seems a strong word to me...It's true that SQL very apparent drawbacks consists of poor duplicates treatment and poor handling of missing data (NULL) but I do not believe these are the worst. Other drawbacks appear more troubling to me into handling better relational requirements are the fact that SQL neither correctly support domain definition, nor it implements any real coherence of what relational data types are.
The main impact is that a better integrity preservation, a core issue,
becomes very difficult to implement.
<<This is what makes SQL hard to replace by a superior language. Keep in
mind that some widely sucessful SQL features like "group-by" are  ad-hock and are not part of the relational model.>>

<< I doubt naive OO method would contribute anything. If you want in-depth
 theory of inheritance, classification then check up formal concept  analysis (Uta Priss has written a nice survey article).>>

Thank you for this source of information. I will check it as soon as I get a chance. I do not using OO in a *replacement* perspective of SQL.  I was more wandering about what features distinctive of OO could bring a better handling of a relational implementation such as in memory representation of RTables (which you will convene I hope is not the same thing).

Thank you for your input.

Mikito Harakiri wrote:
> Cimode wrote:
> > In a word, I am
> > under the impression that SQL (which was not initially thought of as it
> > is now) is becoming a limitation of the relational model.
>
> This is urban myth. SQL is widely criticised for its NULL and duplicate
> treatment. There is several more little annoying inconsistencies.
> That's about it. On practice, I fire SQL query and rarely get a
> surprising result that can be attributed to SQL deficiency.
>
> This is what makes SQL hard to replace by a superior language. Keep in
> mind that some widely sucessful SQL features like "group-by" are
> ad-hock and are not part of the relational model.
>
> > Which is why
> > a question may be asked which is: can OO bring something to that? I
> > kept hearing about OO fuss about so many years that I am interested now
> > as what it may concretely bring to relational implementation... For
> > instance inheritance is something that may prove extremely useful in
> > the implementation of subtype/supertype RTables.
>
> I doubt naive OO method would contribute anything. If you want in-depth
> theory of inheritance, classification then check up formal concept
> analysis (Uta Priss has written a nice survey article). Formal concept
> analysis provides a nice set-theoretic model for many OO artifacts such
> as multiple inheritance, for instance.
Received on Thu Jun 01 2006 - 21:06:40 CEST

Original text of this message