Re: SERIAL Field

On 6 May 2002 at 10:51, Joel Burton wrote:

> > But the very idea of inserting the value and then retriving the sequence
> > number sounds fishy to me. Why not get the sequence number first and than
> > insert using that seqnce number (more on the flash tutorial ).

That's pretty standard in a number of database applications (i.e. not just
PostgreSQL situations).

> Hmmm... does nextval() 'hold' a sequence number for this backend?
> Otherwise, the risk would be that you request a value, and someone else has
> beat you to it before you insert it.

I use nextval all the time.  In fact:

fp2migration=# \d users
 Column | Type       |   Modifiers
------------+--------------------------+--------------------------
 id         | integer     | not null default nextval('users_id_seq'::text)

What's wrong this this?  Nobody is going to "beat me to it".

> In any event, inserting then using currval() is the standard practice
> around here, and it works great. Nothing fishy at all here, nothing to see,
> move on.

Why is that "less risk"?
--
Dan Langille
The FreeBSD Diary - http://freebsddiary.org/ - practical examples