Dave Howorth wrote:
> Dave Howorth wrote:
>
>>> So that's why Class::DBI::mysql ends up behind Class::DBI in the
>>> inheritance and in consequence the wrong version of column_type
>>> gets called.
>>
>>
>> It's late and I'm going to bed now :)
>>
>> It needs a clearer mind to think about a proper patch.
>
>
> Last night, I missed stating what I see as the requirements for a solution:
>
> (A) The M-M-CDBI model base class should not inherit from C-DBI.
> It should first call C-DBI-Loader, which decides the appropriate flavour
> of C-DBI to inherit from (C-DBI-mysql, C-DBI-SQLite etc) and creates all
> the classes for the tables with that base class.
>
> (B) But the other useful thing that the M-M-CDBI base class does is to
> _use_ all the additional C-DBI-* modules (AsForm, FromCGI etc). To do
> that, for some of them at least, it needs to inherit from C-DBI or a
> subclass (so the C-DBI-* modules can call set_sql in their startup).
>
> So that's the dilemma. M-M-CDBI shouldn't inherit from C-DBI (A), and it
> should (B).
>
> Now it's morning, I see an obvious evil patch that's a variation of my
> experiment last night. Simply start with the original M-M-CDBI that
> *does* inherit from C-DBI so that all the C-DBI-* modules can be used.
> Then at the end of setup_database(), once the loader-determined C-DBI
> subclass is known, _remove_ C-DBI from M-M-CDBI's @ISA and substitute
> the C-DBI subclass.
Unfortunately, that'll break under mod_perl if you have one app using a
Mysql datasource and another using some other datasource such as Pg or
SQLite.
One solution is to remove Class::DBI entirely from M::M::CDBI's @ISA and
make your table classes inherit from a new base class. Consider the
following inheritance model:
@MyApp::Model::Table::ISA = (MyApp::Model::_CDBI)
@MyApp::Model::_CDBI::ISA = (M::M::CDBI, Class::DBI::$driver)
@Maypole::Model::CDBI::ISA = (M::M::Base)
M::M::CDBI can defer loading of Class::DBI::RetrieveAll, etc until the
new base class is created. And $r->config->model remains near the front
of your table classes' @ISA, where it belongs.
M::M::CDBI::Plain needs a slightly different strategy since you can use
it to connect to multiple CDBI datasources.
I'll have a think about more inspiring solutions...
--simonflk
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