Re: Can relational alegbra perform bulk operations?

From: Banana <Banana_at_Republic.com>
Date: Tue, 29 Sep 2009 12:55:40 -0700
Message-ID: <4AC2663C.5070304_at_Republic.com>



Bob Badour wrote:
> What you appear to be looking for is a physical structure not a logical
> one, which in SQL one would build with the "CREATE INDEX" statement.

Well, I do apologize if I provided the impression that I was looking for the physical structure or implementation. In fact, what I'm trying to visualize the practicality relational theory has for any given implementation, and I can obviously see how it applies in logical design (or at least I hope I did understand it correctly), however, the same book I mentioned in my OP did mention (too briefly, alas) how relational theory can help optimize queries, which I tried to illustrate in my OP citing the joins' commutative property to transform an expression into a equivalent expression that may be computationally simpler to resolve.

With that said, I am trying to understand whether it provides us with a mechanism of evaluating relations as a set without requiring iterations as I attempted to explain in my other post to Tegiri.

I hope this helps clarifies my quest toward a more solid understanding of the theory. Received on Tue Sep 29 2009 - 14:55:40 CDT

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