DBIx::Class::SQLMaker::Role::SQLA2Passthrough - A test of future possibilities

NAME  SYNOPSIS  SETUP  expand_join_condition  on 

---

NAME

DBIx::Class::SQLMaker::Role::SQLA2Passthrough − A test of future possibilities

SYNOPSIS

	•		select and group_by options are processed using the richer SQLA2 code
	•		expand_join_condition is provided to more easily express rich joins

See "examples/sqla2passthrough.pl" for a small amount of running code.

SETUP

(on_connect_call => sub {
my ($storage) = @_;
$storage−>sql_maker
−>with::roles('DBIx::Class::SQLMaker::Role::SQLA2Passthrough');
})

expand_join_condition

__PACKAGE__−>has_many(minions => 'Blah::Person' => sub {
my ($args) = @_;
$args−>{self_resultsource}
−>schema−>storage−>sql_maker
−>expand_join_condition(
$args
);
});

on

__PACKAGE__−>has_many(minions => 'Blah::Person' => on {
{ 'self.group_id' => 'foreign.group_id',
'self.rank' => { '>', 'foreign.rank' } }
});

Or with ParameterizedJoinHack,

__PACKAGE__−>parameterized_has_many(
priority_tasks => 'MySchema::Result::Task',
[['min_priority'] => sub {
my $args = shift;
return +{
"$args−>{foreign_alias}.owner_id" => {
−ident => "$args−>{self_alias}.id",
},
"$args−>{foreign_alias}.priority" => {
'>=' => $_{min_priority},
},
};
}],
);

becomes

__PACKAGE__−>parameterized_has_many(
priority_tasks => 'MySchema::Result::Task',
[['min_priority'] => on {
{ 'foreign.owner_id' => 'self.id',
'foreign.priority' => { '>=', { −value => $_{min_priority} } } }
}]
);

Note that foreign/self can appear in such a condition on either side, BUT if you want DBIx::Class to be able to use a join−less version you must ensure that the LHS is all foreign columns, i.e.

on {
+{
'foreign.x' => 'self.x',
'self.y' => { −between => [ 'foreign.y1', 'foreign.y2' ] }
}
}

is completely valid but DBIC will insist on doing a JOIN even if you have a fully populated row object to call "search_related" on − to avoid the spurious JOIN, you must specify it with explicit LHS foreign cols as:

on {
+{
'foreign.x' => 'self.x',
'foreign.y1' => { '<=', 'self.y' },
'foreign.y2' => { '>=', 'self.y' },
}
}

---