Re: Object-relational impedence

From: topmind <>
Date: Mon, 17 Mar 2008 09:12:22 -0700 (PDT)
Message-ID: <>

On Mar 17, 6:44 am, Eric <> wrote:
> On 2008-03-16, S Perryman <> wrote:
> ...
> > For the real-world systems involving "variant records" that I have worked
> > on (100+ different record types, 100+ different property types) your table
> > is merely a global variable from hell (as evidenced by the several telecoms
> > systems that used the same approach in the 1990s and ended up being a
> > lifetime rewrite and rebuild job whenever types and properties came and
> > went) .
> If you build a system around something like that, you are crazy. If it
> is a given that you have to deal with, all you can do is treat it as
> messages and parse them to put the information you need into sensible
> structures. This is probably true for a much smaller number of variants.
> E

I suspect his system needed a many-to-many table(s) somewhere, but instead they hardwired many categories into columns and created myriad tables for each (forced) "subtype", like he did in the Publications example from a month or so ago. Perhaps in the 1990's RDMBS performance wasn't good enough to handle many-to-many tables that way. But he still holds a grudge against RDBMS.

-T- Received on Mon Mar 17 2008 - 11:12:22 CDT

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