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Hi,
nextval('seq_name') will never return the same number twice (even if multiple transaction call it at the same time). Of course I would still agree you'd want a unique index on a unique column still.
Cheers,
- Stuart
P.S. Sorry about the disclaimer adder changing the format :(
> -----Original Message-----
> From: Pete Hatton [mailto:pete@xxxxxxxxxxxxx]
>
> > Hi, thanks for this idea.
> > As this reqiures 2 SQL commands, I am worried that there may be some
> > problems if this procedure should be run by a different
> user inbetween
> > these commands. I would consider transaction locking,
> however sequences
> > values are not locked. Any ideas on how to secure this?
> >
> Not used Postgresql myself, but my thoughts are make to make
> the field
> that usess the sequence number a primary key or a index with
> no duplicates.
>
> Then witb a commit and rollback it shouldn't cause any problems.
>
> eg
>
> begin transaction
> sql to get next sequence number
> insert data into table
> if insert fails due to a primary key constraint or index constraint
> rollback
> else
> commit
>
> Stored procedures are you friend here :)
>
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