Re: primary key and existing unique fields

Since you already have the unique field I see no point in adding a sequence
to the table, unless of course the sequence of the data inserts is of
importance at some point.

Duane

-----Original Message-----
From: Sally Sally [mailto:dedeb17(at)hotmail(dot)com]
Sent: Tuesday, October 26, 2004 9:25 AM
To: pgsql-general(at)postgresql(dot)org
Subject: [GENERAL] primary key and existing unique fields

Hi all,
I am wandering about the pros and cons of creating a separate serial field
for a primary key when I already have a single unique field. This existing
unique field will have to be a character of fixed length (VARCHAR(12))
because although it's a numeric value there will be leading zeroes. There
are a couple more tables with similar unique fields and one of them would
need to reference the others. Does anybody see any good reason for adding a
separate autoincrement primary key field for each table? or either way is
not a big deal.
Sally

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