Re: [SQL] Looking for comments

[Peter Eisentraut]

Thomas SMETS writes:

> <snip>
> ISBN's have a checkdigit; it would be sensible to provide a
> function to be used in a CHECK constraint to ensure that the
> ISBN is valid.
> </snip>
>
> OK I'll start searching for it but haven't implemented yet

In the PostgreSQL distribution there's a directory contrib/isbn_issn that
defines a couple of data types that might help you.

-- 
Peter Eisentraut      [EMAIL PROTECTED]       http://yi.org/peter-e/