Re: Re: Re: Rules, views, sequences and returned values

On Fri, Mar 23, 2001 at 12:23:35PM -0500, Gregory Wood wrote:
> > i'm sure there's a reason for this--
> >
> > psql=> select currval('mytable_afield_seq') ;
> > ERROR: mytable_afield_seq.currval is not yet defined in this session
> >
> > but i'll be darned if i can figure out what it is. (after one
> > call to "nextval()" currval() works fine, of course.) someone hit
> > me with a clue stick!
>
> currval() is the value last used by the backend, not by the database.
> Meaning that you have to actually use the sequence before the backend has a
> value to retrieve. That means either doing a nextval() or doing an INSERT
> (which implicitly performs the nextval() ).

<dense mode=on>
seems like the backend (server?) would know the current value of
a sequence, since it has to get it, then add one to it, to get
the next one in line. if george inserts a record, i'd think that
ringo would be able to see the current counter afterwards,
independent of session...

so i can't retrieve and use the existing current value for a
sequence unless i bump it one? me no grok.
</dense>

--
It is always hazardous to ask "Why?" in science, but it is often
interesting to do so just the same.
-- Isaac Asimov, 'The Genetic Code'

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