Re: Object-oriented thinking in SQL context?
Date: Wed, 10 Jun 2009 10:20:45 GMT
"Bernard Peek" <bap_at_shrdlu.com> wrote in message
> I'm an enthusiastic Access user although I'm far from being an expert. But
> I know that it does have some serious weaknesses and in some situations
> actively encourages bad practise.
> That's where a decision is required. Do you want to learn Access or do you
> want to learn relational theory. The two are related but they aren't the
> same thing.
>>There is one antipattern that I want to mention in particular. Your
>>description, in the original post, reminds me of the
>>(EAV) antipattern. Different insrument types are like different entities,
>>different calibrations are like different attributes, and different
>>measurements are like different values. The terible thing about EAV is
>>hell you have to go through to create meaningful queries out of that mess,
>>if you're using SQL or any language remotely like it.
> That's one of its many disadvantages. It's another one of the ideas that
> visitors to this newsgroup occasionally espouse as the next Big Thing.
The people who consider EAV the next Big Thing generally do so because it permits one to design a database without understanding the data at all. This enables one to skip right over that messy, tedious, and time consuming process of interviewing people who work with the data to find out how it really works.
No analysis. Simple, universal design. On to implementation. Meaningful outputs? We'll worry about that later.
Actually, I kinda hoping our OP will read some of the articles on "generalization specialization relational modeling" and use the ideas to design the tables. I can't be sure, but I think he'll get more return on investment than he will going the EAV route. The best article actually starts out showing how to do gen-spec ER modeling, and treats that as if it were relational modeling. I use ER modeling myself with no apologies to anyone, but ER modeling and relational data modeling are different, as several regulars always point out. Received on Wed Jun 10 2009 - 12:20:45 CEST