Re: Constraints and Functional Dependencies

From: Bob Badour <>
Date: Tue, 06 Mar 2007 15:42:58 GMT
Message-ID: <6_fHh.7025$>

Walt wrote:

> "Marshall" <> wrote in message

>>On Feb 24, 2:08 pm, "Walt" <> wrote:
>>>"Marshall" <> wrote in message
>>>>On Feb 24, 6:41 am, paul c <> wrote:
>>>>>Marshall wrote:


> Natural joins are easier to express, and easier to resolve. It depends on
> what metadata is used to set up the natural joins, I guess. But if you
> always use the primary key for reference, it strikes me that the resolution
> of natural joins has a smaller search space.

The algebra defines a natural join on the names of the attributes and not on the declared keys. Thus, declaring a primary key has no effect on the search space. Received on Tue Mar 06 2007 - 16:42:58 CET

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