Re: repository GUIDs

Bill Tutt wrote:

> The new table under discussion is an example of wanting to index a table
> by an Alternative Key, and here's an example of indexing a table by a
> non-unique key:
>
> Searching for Businesses in a Yellow Pages system:
> There are several million businesses in the US. It turns out the most
> efficient business search queries result out of indexing the Business
> table by (ZipCode, BusinessID) as opposed to just by BusinessID.

Terminology nit: that's not a non-unique key; that's a superkey. It
uniquely identifies a business, but not all included attributes are
necessary to do so. BusinessID is a "candidate key" or "primary key" if
you choose to call it so.

Thanks,
Scott the RDBMS Nazi

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Received on Fri Dec 13 00:00:26 2002