Re: One sequence for different tables

On Mon, 11 Mar 2002, Stephan Szabo wrote:

You can add a trigger, BEFORE INSERT on each table to check the key in the
other table to prevent cross table duplications. I have done this in the
past, but I no longer do. It didn't work as well as I intended. I also
occasionally got duplicates anyway, which I could never explain. But that
was way back on a 6.? server I used to have.

- brian

> On Mon, 11 Mar 2002 Robert(dot)Farrugia(at)go(dot)com(dot)mt wrote:
>
> > Is it possible to create one sequence to be used for more than one table ?
> > Let's say I create a pkey_seq sequence.
> > Can I use it in table A (pkey default nextval('pkey_seq') PRIMARY KEY) and
> > in table B as (pkey default nextval('pkey_seq') PRIMARY KEY) ?
>
> Yes.
>
> > Is it safe in that each table will have unique values i.e. if I have a
> > third table C which is used to link data both from A and B using the pkey
> > field, will there be records having the same pkey but from different
> > tables?
>
> As long as you never insert an explicit value into the column and don't
> have to roll over the sequence, you should be safe.
>
>
>
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