Re: OO and relation "impedance mismatch"

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Sat, 02 Oct 2004 17:23:12 +0200
Message-ID: <415ec7e4$0$65124$e4fe514c_at_news.xs4all.nl>


Troels Arvin wrote:
> Fredrik Bertilsson wrote:

>>OO people often claims that there are an impedance mismatch between
>>the OO model and the relational model, that makes it very hard use a
>>relational database when you are using an OO programming language.

> ... Then there is type support:
> Some of the data types found in - e.g. - SQL
> don't have out-of-the box, perfectly
> matching types in the major OO languages.

[snip paradigms, n-tier]

> I think that the impedance mismatch would be less of a problem, if
(summary: )
RDBMS
1. RDBMSes got better at useful error reporting. 2. Relations in RDBMSes were easier to query for

    metainformation.
The OO World would
3. - cut down on the fear for coupling, and 4. - accept RDBMS-software as valid, powerful technology.

By now I hoped for a proposal for putting energy into a common datatype standard, supported by/supporting programming languages and DBMS.

I suspect you would like to see such a thing - or did you have a reason not to go into that part of the problem?

> The result of 1 and 2 could be less middleware "obesity"
> problems and more centralized constraint handling.
> Points 3 and 4 are actually wishes for less tendentious
> religiosity in the OO World: OO is a (sometimes) practical
> way to organize code, not an ever good, all-encompassing
> computing ideology.

IMO common datatypes could help address
frequently encountered mismatches.

> While facing the risk of being seen as a make-love-not-war tech hippie, I
> suggest that the term "impedance mismatch" should be terminated and
> replaced with something less pessimistic, such as "practical
> issues in combination of forces".

These problems are addressed in actual practise every day. The resulting systems would not survive if they weren't. However, because they are not yet taken care of enough at an abstract level, the same problems recur over and over again.

BTW: Nice reading, this. Thank you, Fredrik and Troels. Received on Sat Oct 02 2004 - 17:23:12 CEST

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