Re: Object-oriented thinking in SQL context?

dr.coffee1_at_gmail.com wrote:
> On 10 Jun, 00:12, "Walter Mitty" <wami..._at_verizon.net> wrote:
>

>><dr.coff..._at_gmail.com> wrote in message
>>
>>news:35fe9916-b423-49e4-95f4-b42bf672a4c7_at_x5g2000yqk.googlegroups.com...
>>
>>>That's what confused me. The general concepts are *similar*
>>>to concepts from OO, but not the same. I suppose the main
>>>difference is that objects are local collections of different
>>>attributes, while in relational databases the objects are
>>>'disassembled' and the attributes distributed over the
>>>various tables.
>>
>>If the mapping between OO concepts and RM concepts were simple,  someone
>>would have, by now, written a book that ties the two of them together, and
>>explains both patterns in terms that makes sense. to someone coming from one
>>pattern or the other.  To my knowledge, there is no such book.  I'm going to
>>echo something Bernard said in another response.
>>Better minds than mine have attempted to reconcile the OO way of thinking
>>and the RM way of thinking with each other.  By their own reckoning,  their
>>attempts have been unsuccessful.

Frankly, your biggest problem is not knowing who to ignore and who to pay attention to.

> Again, the concepts are so
> *similar* that it's an obvious idea to anyone coming from the
> OO side to at least ask why they aren't expressed in OO form.
> And again, I start to get an impression what the problem is:
>
> OO philosophy is founded on 'encapsualization', where attributes
> are collected into 'objects' that make some sort of sense in
> the problem (business) domain. Relational databases are all
> about breaking that encapsualization, to efficiently search
> for information.

Your ignorance is showing. "Encapsulation" is just a syntactic/physical implementation of a specific type of the general engineering principle of "information hiding". The RM addresses the same principle much more powerfully and much more completely through data independence.

>>So you really shouldn't expect to reduce RM to a pattern that you already
>>know.  And you shouldn't expect, based on your success with OO up to this
>>point,  to be able to treat RM as something that can be marginalized as
>>either a specialized niche or a trivial development.  It is neither.

A brick is trivial. An n-dimensional relation of "object" values is not. You seem rather impervious to grasping the simplest of observations even when pointed out to you. Received on Wed Jun 10 2009 - 16:08:19 CEST