[Dbix-class] 08100: branch roundup, owners please respond.

[John Napiorkowski]

--- Matt S Trout <dbix-class at trout.me.uk> wrote:

> On Mon, Mar 31, 2008 at 06:17:26PM -0700, John
> Napiorkowski wrote:
> > Okay, so I think this is actually much easier than
> I
> > first thought.  Basically since I know that each
> > storage specific subclass inherits from
> > DBIx::Class::Storage::DBI I just put a stublike
> method
> > there which performs the connection and
> redispatches
> > to the subclass on an as needed basis.
> > 
> > So for example, if a storage specific subclass
> needs
> > to define bind parameters, such as how the Pg
> Storage
> > subclasses needs to set bytea bind parameters to
> > support using bytea for long/blob storage, it
> > overrides the method "bind_attribute_by_data_type"
> > from DBIx::Class::Storage::DBI like so:
> > 
> > sub bind_attribute_by_data_type {
> >   my ($self,$data_type) = @_;
> > 
> >   my $bind_attributes = {
> >     bytea => { pg_type => DBD::Pg::PG_BYTEA },
> >   };
> >  
> >   if( defined $bind_attributes->{$data_type} ) {
> >     return $bind_attributes->{$data_type};
> >   }
> >   else {
> >     return;
> >   }
> > }
> > 
> > and in the parent class I have a version which, if
> > executed, performs the connection and then sends
> it
> > off to the storage specific subclass:
> > 
> > sub bind_attribute_by_data_type {
> >   my ($self, $data_type, $storage) = @_;
> >   if($storage) {
> >     $storage->ensure_connected;
> >     return
> > $storage->bind_attribute_by_data_type($data_type)
> >   }
> >   return;
> > }
> 
> You need to trap the case where it isn't overrided
> in the subclass. So
> something like
> 
> our $NO_SUBCLASS;
> return if $NO_SUBCLASS;
> $self->ensure_connected;
> local $NO_SUBCLASS = 1;
> $self->bind_...
> 
> or similar. Or maybe
> 
> sub bind_... {
>   $self->ensure_connected;
>   $self->_bind_... # note the _
> 
> which is probably simpler and harder to get wrong.

Yeah, I was worried about that as well.  I tested it
on a few databases without trouble, but was concerned
it's starting to be a little too much action at a
distance and the kind of thing that will lead us to
troublesome bugs.  Since this fix is for such a tiny
edge case I don't want to make things worse.  

> 
> The other thing to consider is: Can we not just do
> ensure_connected on the
> way in to anything that's going to use the dbh
> (insert, select etc.) so
> specific methods don't have to worry about it at
> all?
> 

>From my testing I found by the time we get to
insert/update, etc it's too late.  Let me give it
another look, since I'd rather have a more general
solution than one that just solves this particular
problem.

--john


> -- 
>       Matt S Trout       Need help with your
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