Tim Bunce wrote:
On Tue, Sep 19, 2006 at 01:41:22PM -0700, Dean Arnold wrote:
I stumbled on an oddity in execute_array() I'm hoping can
be clarified (it maybe a bug, or just an undoc'd requirement
of driver authors)
The following bit of code appears to require that the hash returned by
ParamArrays use monotonically increasing integers as keys:
my %hash_of_arrays = %{$sth->{ParamArrays}};
....some code here....
my @bind_ids = 1..keys(%hash_of_arrays);
my $tuple_idx = 0;
$fetch_tuple_sub = sub {
return if $tuple_idx >= $maxlen;
my @tuple = map {
my $a = $hash_of_arrays{$_};
ref($a) ? $a->[$tuple_idx] : $a
} @bind_ids;
++$tuple_idx;
return [EMAIL PROTECTED];
};
But the ParamArrays docs indicate that the returned hash can
use something other than integers as keys.
Umm. Good point.
It's related to the fact that if you use 'named' placeholders with a
non-array statement then you have to use bind_param() and not supply
any bind values to execute().
The problem with execute_array is that it's built on execute_for_fetch
and that requires an ordered set of bind values.
I've worked around this by implementing an internal mapping
so that named parameters have a matching positional value,
which is used when ParamArrays/ParamValues are assigned
within bind_param{_array]().
<snip>
I think I'm going to take the view that all drivers should support
'?' style placeholders and that those should be used for execute_array
and execute_for_fetch.
For database that don't support '?' style placeholders it's pretty
trivial for the driver to rewrite them as 'p1', 'p2' etc etc.
That's exactly what DBD::Oracle as always done.
Just so I'm clear:
"DBI's default execute_array()/execute_for_fetch() requires the use of
positional (i.e., '?') placeholders. Drivers which B<require> named
placeholders must implement their own execute_array()/execute_for_fetch()
methods to properly sequence bound parameter arrays."
Could you update the docs? (If you don't have write access to the dbi
repository yet, send me your auth.perl.org username and I'll give it to you.)
Tim.
OK, after I finish up my release to shake out anything else. I've got a few
other items I'd like to note in the DBI::DBD pod wrt ParamValues/ParamArrays...
actually, I'm going to try and a create a detailed list of attributes
that do or don't get forwarded to a driver's STORE/FETCH methods...ParamValues/
ParamArrays gave me fits until I figured out DBI didn't route them thru
my FETCH(). Plus the strangeness of _new_sth() wrt which attributes it will
save and which it won't.
- Dean
