On Mon, Jun 23, 2003 at 05:16:51PM +0100, Dominic Mitchell wrote:
> >Note that this is quite safe and the value returned is the current value
> >for YOUR session only; so no need to worry about someone else inserting
> >something or other such race conditions. :)
>
> Doesn't that depend on whether you're in a transaction or not? I would have
> thought that you're liable to have it updated if you've got AutoCommit
> turned on.
No, it's still correct even outside of sequences. the current value returned
is always the value for your session.
> I don't know this, I'm just making assumptions about how sequences work. :-)
tut tut ;)
> ># Returns the last ID resulting from an INSERT command
> >sub last_inserted_id
> >{
> > my $self = shift;
> > my $table = shift; #should be safe, but check anyway
> > if ($table =~ /(\w[\w\d\_]+)/) {
> > $table = $1;
> > }
> > else {
> > die("LBHF.pm/last_inserted_id: Invalid table name: $table\n");
> > }
> > my $query = $self->{db}->prepare("SELECT currval('" . $table .
> > "_id_seq')"); $query->execute
>
> Hmmm, big assumptions about sequence names here. I merely point this
> out because I'm continually getting annoyed at postgres for truncating
> min to 32 chars. This is because I include the table name in my primary
> key column name though...
True, but (currently) that is the way Postgresql generates sequence names from
serials. Using this assumption works well enough for my internal code.
tjc
