On Sun, Feb 13, 2005 at 05:54:40PM -0800, David Wheeler wrote:
> On Feb 13, 2005, at 2:44 PM, Tim Bunce wrote:
>
> >The DBD::_::connect method then becomes just something like
> >
> > my $dbh = $drh->new_child($attr) or return;
> > $dbh->connect(...) or return;
> > return $dbh;
> >
> >then we kindly ask driver authors to remove their DBD::foo::dr::connect
> >method (so the DBI's default one get used) and implement most of
> >the logic in a new DBD::foo::db::connect method instead.
> >
> >(The same applies to DBD::foo::db::prepare.)
>
> That sounds fairly straight-forward for them. Generally, it would just
> involve moving connect() to a different package, yes?
Yes. That much should be trivial for them. The more tricky issue is
that it affects how attributes are handles.
Currently the drivers connect() method can process the contents of
\%attr directly. Many support connect() atributes that are not
supported as handle attributes. In other words, currently:
$dbh = DBI->connect(..., { foo_bar => 42 }); # ok
$dbh->{foo_bar} = 42; # not ok
With the new logic the attributes are all stored in the handle
before the drivers connect method gets called. So drivers have
to "go fishing" for all possible driver attributes relevant to the
connnect and get the current values from the handle.
Not a big deal, but definitely another change and scope for problems.
[On the roadmap/todo there's an item about recording the names of
all attributes that have been set on a handle. That may also be
useful here so drivers can be led by what attributes have actually
been set rather than having to go check every possible attribute.]
> >One way would be to have the driver provide a DBI version
> >compatibility value.
> >If set to high enough version then the DBI's (internal) load_driver
> >method
> >would delete DBD::foo::dr::connect if DBD::foo::db::connect exists.
>
> Yes, because then the DBI can leave it if there is no
> DBD::foo::db::connect, such as in older versions of the drivers. That
> doesn't sound so bad to me...am I insane? :)
Perhaps we both are :)
> >Are you having fun yet? :)
>
> I'm having a blast. I think I'll just implement my own handle caching
> code, for now, to prevent the resetting of AutoCommit which is, after
> all, all I need right now. But I'd be happy to help with the other
> projects so that I can eventually go back to using connect_cached
Sounds good to me! Thanks.
More generally, I'm very open to people volunteering to work on DBI
enhancements from the roadmap/todo. Subversion branches make it easy
for multiple people to be working on enhancements that scratch
their own itches, without getting in the way of others or the mainline.
Tim.
