Re: Modelling objects with variable number of properties in an RDBMS

In message <2D89f.3422$AS6.3019_at_newsread3.news.atl.earthlink.net>, David Cressey <david.cressey_at_earthlink.net> writes

>There is a very simple reason why people keep reinventing E-A-V.
>
>They want all the benefits that go with structured data together with all
>the benefits that go with unstructured data.
>They aren't sophisticated enough to see the trade-off in advance.
>
>They don't understand the down side of that design until after they have
>shot themselves in the foot.

Sometimes they have changed jobs by then. Then it's the person who succeeds them who wants to shoot them.

>
>After that, some of them learn, and do better on their next project.
>Others keep making the same mistake, over and over again, and blame the
>consequences on the tools they are using.

That's one reason why people keep trying to use it. The second one, unfortunately, is that sometimes it's the only alternative. Sometimes you just don't know the whole data structure at design-time.

-- 
Bernard Peek
London, UK. DBA, Manager, Trainer & Author.