Posted by Gordon Burditt on 07/20/05 19:12

>I don't really understand the difference between primary key and
>unique. Should I use primary key instead of unique?

A primary key is, essentially, the first unique index. The distinction
is mostly for the programmer and automatic tools that diagram
relationships between tables.

How do you tell which of a pair of twins is the twin, and which one
is a real child?

Gordon L. Burditt

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