On Wed, 26 Feb 2003, Tim Bunce wrote:
> > I know there is a {NUM_OF_PARAMS} attribute and a {ParamValues} attribute,
> > but is there a way to get the names of :foo style params before they are
> > bound?
>
> Umm, not officially currently but there's a good chance that keys
> %{$sth->{ParamValues}} would work on many drivers that support it.
>
> I'll add a note to that effect in the docs so that'll become the
> standard way.
>
> A slight downside is that it won't be possible to tell the difference
> between a placeholder that's not been bound and one that has but
> was bound to undef. But I don't think that'll be a big issue.
> Anyone disagree?
Humm. I don't know. I just stated playing with named placeholders and have
not compleatly hashed this out, but I have been going down the lines of
using :foo with data structs that match the param names so I can just
iterate and bind instead of having to count placeholers or having to
create an array of '?'s and an array of data to send to execute. So:
# set params to hash of params.
while (my ($k,$v) = each %data) {
$sth->bind_param(":$k",$v);
}
# or more cleanly
for (qw( list of names to bind) {
}
But what would be nice to be able to do (and what motivated my qustion),
is to just grab the list of placeholders from the DBD since it
already knows. like:
for (kyes %{$sth->{ParamValues}) {
unless ($bind_undef_to_unkown && exists $data{$_}) {
$sth->bind_param($_, undef);
}
$sth->bind_param($_, $data{$_})
}
$sth->execute();
The problem that I see with the above is if $bind_undef_to_unknown is
false :unbound would keep its value from the last call. The loop could
probably thow an exception if $bound_undef... is false and the data
element does not exist. So I guess I would like soemthing that does not
tell me whether a placeholder has been bound but more something that lets
me reset the "bound status" (But not for type binding, just for execute)
As an example:
eval {
$sth->bind_hash(\%data, {bind_undef_to_unkown=>1}); #
$sth->execute(); # Throws error on unbound param.
$sth->reset_bind(); # reset so some other f(x) does not get our params.
$sth1->bind_hash(\%data1);
$sth1->execute; # remembers bindings not in %data1
}; if (my $e = @_) {
...
}
Thoughts? Make sense? Am I loosing it?
-r
