Say you want to run a complex custom query on your user data, here's what
you have to add to your User class:
- package My::Schema::User;
+ package My::Schema::Result::User;
use base qw/DBIx::Class/;
achieve the same with subclassing the resultset class and defining the
ResultSource there:
- package My::Schema::UserFriendsComplex;
+ package My::Schema::Result::UserFriendsComplex;
- use My::Schema::User;
- use base qw/My::Schema::User/;
+ use My::Schema::Result::User;
+ use base qw/My::Schema::Result::User/;
__PACKAGE__->table('dummy'); # currently must be called before anything else
=head2 SELECT DISTINCT with multiple columns
- my $rs = $schema->resultset('Foo')->search(
+ my $rs = $schema->resultset('Artist')->search(
{},
{
- select => [
- { distinct => [ $source->columns ] }
- ],
- as => [ $source->columns ] # remember 'as' is not the same as SQL AS :-)
+ columns => [ qw/artistid name rank/ ],
+ distinct => 1
+ }
+ );
+
+ my $rs = $schema->resultset('Artist')->search(
+ {},
+ {
+ columns => [ qw/artistid name rank/ ],
+ group_by => [ qw/artistid name rank/ ],
}
);
+ # Equivalent SQL:
+ # SELECT me.artistid, me.name, me.rank
+ # FROM artist me
+ # GROUP BY artistid, name, rank
+
=head2 SELECT COUNT(DISTINCT colname)
- my $rs = $schema->resultset('Foo')->search(
+ my $rs = $schema->resultset('Artist')->search(
{},
{
- select => [
- { count => { distinct => 'colname' } }
- ],
- as => [ 'count' ]
+ columns => [ qw/name/ ],
+ distinct => 1
}
);
- my $count = $rs->next->get_column('count');
+ my $rs = $schema->resultset('Artist')->search(
+ {},
+ {
+ columns => [ qw/name/ ],
+ group_by => [ qw/name/ ],
+ }
+ );
+
+ my $count = $rs->count;
+
+ # Equivalent SQL:
+ # SELECT COUNT( * ) FROM (SELECT me.name FROM artist me GROUP BY me.name) count_subq:
=head2 Grouping results
so no additional SQL statements are executed. You now have a much more
efficient query.
-Note that as of L<DBIx::Class> 0.05999_01, C<prefetch> I<can> be used with
-C<has_many> relationships.
-
Also note that C<prefetch> should only be used when you know you will
definitely use data from a related table. Pre-fetching related tables when you
only need columns from the main table will make performance worse!
=head2 Multi-step prefetch
-From 0.04999_05 onwards, C<prefetch> can be nested more than one relationship
+C<prefetch> can be nested more than one relationship
deep using the same syntax as a multi-step join:
my $rs = $schema->resultset('Tag')->search(
AKA getting last_insert_id
-If you are using PK::Auto (which is a core component as of 0.07), this is
-straightforward:
+Thanks to the core component PK::Auto, this is straightforward:
my $foo = $rs->create(\%blah);
# do more stuff
# do whatever else you wanted if it was a new row
}
+=head2 Static sub-classing DBIx::Class result classes
+
+AKA adding additional relationships/methods/etc. to a model for a
+specific usage of the (shared) model.
+
+B<Schema definition>
+
+ package My::App::Schema;
+
+ use base DBIx::Class::Schema;
+
+ # load subclassed classes from My::App::Schema::Result/ResultSet
+ __PACKAGE__->load_namespaces;
+
+ # load classes from shared model
+ load_classes({
+ 'My::Shared::Model::Result' => [qw/
+ Foo
+ Bar
+ /]});
+
+ 1;
+
+B<Result-Subclass definition>
+
+ package My::App::Schema::Result::Baz;
+
+ use strict;
+ use warnings;
+ use base My::Shared::Model::Result::Baz;
+
+ # WARNING: Make sure you call table() again in your subclass,
+ # otherwise DBIx::Class::ResultSourceProxy::Table will not be called
+ # and the class name is not correctly registered as a source
+ __PACKAGE__->table('baz');
+
+ sub additional_method {
+ return "I'm an additional method only needed by this app";
+ }
+
+ 1;
+
=head2 Dynamic Sub-classing DBIx::Class proxy classes
AKA multi-class object inflation from one table
B<Schema Definition>
- package DB::Schema;
+ package My::Schema;
use base qw/DBIx::Class::Schema/;
- __PACKAGE__->load_classes(qw/User/);
+ __PACKAGE__->load_namespaces;
+
+ 1;
B<Proxy-Class definitions>
- package DB::Schema::User;
+ package My::Schema::Result::User;
use strict;
use warnings;
print "I am a regular user.\n";
return ;
}
+
+ 1;
+
-
- package DB::Schema::User::Admin;
+ package My::Schema::Result::User::Admin;
use strict;
use warnings;
- use base qw/DB::Schema::User/;
+ use base qw/My::Schema::Result::User/;
sub hello
{
{
print "I am doing admin stuff\n";
return ;
- }
+ }
+
+ 1;
B<Test File> test.pl
use warnings;
use strict;
- use DB::Schema;
+ use My::Schema;
my $user_data = { email => 'someguy@place.com',
password => 'pass1',
password => 'pass2',
admin => 1 };
- my $schema = DB::Schema->connection('dbi:Pg:dbname=test');
+ my $schema = My::Schema->connection('dbi:Pg:dbname=test');
$schema->resultset('User')->create( $user_data );
$schema->resultset('User')->create( $admin_data );
L<callback system|DBIx::Class::ResultSource/sqlt_deploy_callback> if you wish
to share a hook between multiple sources):
- package My::Schema::Artist;
+ package My::Schema::Result::Artist;
__PACKAGE__->table('artist');
__PACKAGE__->add_columns(id => { ... }, name => { ... })
projects / dbsrgits/DBIx-Class.git / blobdiff