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All the Perl that's Practical to Extract and Report

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  • My brain is hurting!

    Okay, not really. But this has been interesting reading.

    • by Ovid (2709) on 2005.12.10 18:53 (#45082) Homepage Journal

      What's really frustrating is that much of the problems associated with nulls would go away if database vendors would start supplying DBMS which enforce relational data (SQL doesn't). First, we would need something called "distributed foreign keys" -- mentioned in the PDF I link to. Next, databases would have to be optimized to handle 6NF, something which is rarely seen, and 1NF, something which is not well-understood. Further, queries would need to return relations. In other words, they would need to returns sets of tuples, not bags of rows. Much of the work that's being done to get around limitations with SQL appears to be applying bandages to crippled systems rather than examing the root cause -- ignoring the relational model.

      The book is making my head hurt, too. One of the things which shocked me is realizing that the "object-relational impedance mismatch" is a myth. It's actually the "object-dbms impedance mismatch". If a DBMS properly supported the relational algebra, object databases would be natural instead of the kludgy, ad hoc affairs we have today. You really should get that book if you're interested in this.

      • I can't believe I'm only now seeing this post...

        Since reading Database In Depth, I've also realized that the object-relational impedance mismatch is a myth. It is a persistent myth, but a myth none the less.

        Here's the quote from that book that I always go back to:

        All of which goes a long way, incidentally, toward explaining why a true "object/relational" system would be nothing more nor less than a true relational system—which is to say, a system that supports the relational model, with all that