Re: OO versus RDB

From: H. S. Lahman <h.lahman_at_verizon.net>
Date: Wed, 05 Jul 2006 14:58:39 GMT
Message-ID: <zsQqg.6242$b9.5205_at_trndny01>

Responding to mAsterdam...

>>>> I also don't understand why you keep bringing up OO development; it 
>>>> is completely OT.  The context here is about application 
>>>> partitioning where one isolates knowledge about data storage and 
>>>> access mechanisms away from the problem solution logic within an 
>>>> application.  That is basic separation of concerns and 
>>>> modularization that one does whether the application is constructed 
>>>> with OO techniques or not.
>>>
>>>
>>> Earlier in this thread you said:
>>>
>>>  > I would suggest even further isolation.  The application solution
>>>  > doesn't care if the data is in an RDB, an OODB, flat files, or clay
>>>  > tablets.  So one should hide the SQL as well.
>>>  >
>>>  > In so doing one can often provide reusable storage access across
>>>  > applications where one only needs to provide a subsystem interface
>>>  > and identity mapping to access the data for a particular context.
>>>  > SQL is particularly suited to this because one is just concatenating
>>>  > identity strings.
>>>
>>> and I asked you to point out the benefits of that approach.
>>> It seems I have to accept a - to me - wrong look at the role
>>> of schemata and databases to see those benefits.
>>
>>
>> I still don't see what this has to do with OO development.

>
>
> So?

Why do you keep bringing up OO?

>> The benefits are the same benefits one  gets from any software 
>> modularization: simplifying subject matters; containment, reuse, and 
>> -- most relevant for this thread -- context-independence.

>
>
> , in casu database independence, at the cost of
> 1. if you have dbms: a lesser facade with roll-your-own abstractions.
> 2. if you haven't: a roll-your-own dbms,
> and in both cases modules still fully dependent on the relevant
> part of the conceptual schema (whether it is coded or not, the latter
> being the toughest spot to be in).
>
> Not really a hard decision.

Exactly my point. For large, complex applications the benefits far outweigh the cost of (1) so there is effectively no decision.

>>>>>>>> However, my objection above was that it is not synonymous with 
>>>>>>>> problem solving because problems can be solved on a computer 
>>>>>>>> with different paradigms than OO.
>>>>>>>>
>>>>>>>>> Data management is done by people.
>>>>>>>>> A DBMS is part of the toolkit.
>>>>>>>>
>>>>>>>>
>>>>>>>> Fine.  Just as problems are solved by people while editors, 
>>>>>>>> compilers, code generators, etc. are tools.
>>>>>>>>
>>>>>>>> The point is that data management and problem solving are quite 
>>>>>>>> different concerns and activities.
>>>>>>>
>>>>>>>
>>>>>>> ?? Data management does not solve problems? Are you sure?
>>>>>>
>>>>>>
>>>>>> It solves problems that are restricted to that realm, such as 
>>>>>> ensuring data integrity.  In a broad sense it can include notions 
>>>>>> like data warehousing but in this context I see it as being about 
>>>>>> the services that a DBMS provides.  It generally does not involve 
>>>>>> solving specific business problems.
>>>>>
>>>>>
>>>>> Why do you only state this for DBMS , it goes mm. for OO as well.
>>>>> I won't bother.
>>>>
>>>>
>>>> I don't follow this at all. 
>>>
>>>
>>> mm.: mutatis mutandis. Just try to fill it in.
>>
>>
>> That doesn't help.  I don't follow what you mean by the comment.  What 
>> goes for OO as well?

>
>
> What part of
> >>>> I won't bother.
> didn't you believe?

OK, that's it for this thread. Making an incomprehensible statement and then asserting that you won't deign to explain what you really meant is not a good basis for rational discussion. Ta-ta.

---

There is nothing wrong with me that could not be cured by a capful of Drano.

H. S. Lahman
hsl_at_pathfindermda.com
Pathfinder Solutions -- Put MDA to Work http://www.pathfindermda.com
blog: http://pathfinderpeople.blogs.com/hslahman Pathfinder is hiring:
http://www.pathfindermda.com/about_us/careers_pos3.php. (888)OOA-PATH Received on Wed Jul 05 2006 - 16:58:39 CEST