1 package DBIx::Class::Schema;
7 use base qw/DBIx::Class/;
9 __PACKAGE__->load_components(qw/Exception/);
10 __PACKAGE__->mk_classdata('class_registrations' => {});
11 __PACKAGE__->mk_classdata('storage_type' => 'DBI');
12 __PACKAGE__->mk_classdata('storage');
16 DBIx::Class::Schema - composable schemas
24 use base qw/DBIx::Class::Schema/;
26 __PACKAGE__->load_classes(qw/Foo Bar Baz/);
30 package My::Schema::Foo;
32 use base qw/DBIx::Class/;
34 __PACKAGE__->load_components(qw/PK::Auto::Pg Core/); # for example
35 __PACKAGE__->table('foo');
42 My::Schema->compose_connection('My::DB', $dsn, $user, $pass, $attrs);
46 my @obj = My::DB::Foo->search({}); # My::DB::Foo isa My::Schema::Foo My::DB
50 Creates database classes based on a schema. This allows you to have more than
51 one concurrent connection using the same database classes, by making
52 subclasses under a new namespace for each connection. If you only need one
53 class, you should probably use L<DBIx::Class::DB> directly instead.
55 NB: If you're used to L<Class::DBI> it's worth reading the L</SYNOPSIS>
56 carefully as DBIx::Class does things a little differently. Note in
57 particular which module inherits off which.
61 =head2 register_class <component> <component_class>
63 Registers the class in the schema's class_registrations. This is a hash
64 containing database classes, keyed by their monikers. It's used by
65 compose_connection to create/modify all the existing database classes.
70 my ($class, $name, $to_register) = @_;
71 my %reg = %{$class->class_registrations};
72 $reg{$name} = $to_register;
73 $class->class_registrations(\%reg);
76 =head2 registered_classes
78 Simple read-only accessor for the schema's registered classes. See
79 register_class above if you want to modify it.
84 sub registered_classes {
85 return values %{shift->class_registrations};
88 =head2 load_classes [<classes>, (<class>, <class>), {<namespace> => [<classes>]}]
90 Uses L<Module::Find> to find all classes under the database class' namespace,
91 or uses the classes you select. Then it loads the component (using L<use>),
92 and registers them (using B<register_class>);
94 It is possible to comment out classes with a leading '#', but note that perl
95 will think it's a mistake (trying to use a comment in a qw list) so you'll
96 need to add "no warnings 'qw';" before your load_classes call.
101 my ($class, @params) = @_;
106 foreach my $param (@params) {
107 if (ref $param eq 'ARRAY') {
108 # filter out commented entries
109 my @modules = grep { $_ !~ /^#/ } @$param;
111 push (@{$comps_for{$class}}, @modules);
113 elsif (ref $param eq 'HASH') {
114 # more than one namespace possible
115 for my $comp ( keys %$param ) {
116 # filter out commented entries
117 my @modules = grep { $_ !~ /^#/ } @{$param->{$comp}};
119 push (@{$comps_for{$comp}}, @modules);
123 # filter out commented entries
124 push (@{$comps_for{$class}}, $param) if $param !~ /^#/;
128 eval "require Module::Find;";
129 $class->throw("No arguments to load_classes and couldn't load".
130 " Module::Find ($@)") if $@;
131 my @comp = map { substr $_, length "${class}::" } Module::Find::findallmod($class);
132 $comps_for{$class} = \@comp;
135 foreach my $prefix (keys %comps_for) {
136 foreach my $comp (@{$comps_for{$prefix}||[]}) {
137 my $comp_class = "${prefix}::${comp}";
138 eval "use $comp_class"; # If it fails, assume the user fixed it
139 $class->register_class($comp => $comp_class);
144 =head2 compose_connection <target> <@db_info>
146 This is the most important method in this class. it takes a target namespace,
147 as well as dbh connection info, and creates a L<DBIx::Class::DB> class as
148 well as subclasses for each of your database classes in this namespace, using
151 It will also setup a ->class method on the target class, which lets you
152 resolve database classes based on the schema component name, for example
154 MyApp::DB->class('Foo') # returns MyApp::DB::Foo,
155 # which ISA MyApp::Schema::Foo
157 This is the recommended API for accessing Schema generated classes, and
158 using it might give you instant advantages with future versions of DBIC.
160 WARNING: Loading components into Schema classes after compose_connection
161 may not cause them to be seen by the classes in your target namespace due
162 to the dispatch table approach used by Class::C3. If you do this you may find
163 you need to call Class::C3->reinitialize() afterwards to get the behaviour
168 sub compose_connection {
169 my ($class, $target, @info) = @_;
170 my $conn_class = "${target}::_db";
171 $class->setup_connection_class($conn_class, @info);
172 $class->compose_namespace($target, $conn_class);
175 sub compose_namespace {
176 my ($class, $target, $base) = @_;
177 my %reg = %{ $class->class_registrations };
180 while (my ($comp, $comp_class) = each %reg) {
181 my $target_class = "${target}::${comp}";
182 $class->inject_base($target_class, $comp_class, $base);
183 @map{$comp, $comp_class} = ($target_class, $target_class);
187 *{"${target}::class"} =
189 my ($class, $to_map) = @_;
190 return $map{$to_map};
192 *{"${target}::classes"} = sub { return \%map; };
194 $base->class_resolver($target);
197 =head2 setup_connection_class <$target> <@info>
199 Sets up a database connection class to inject between the schema
200 and the subclasses the schema creates.
204 sub setup_connection_class {
205 my ($class, $target, @info) = @_;
206 $class->inject_base($target => 'DBIx::Class::DB');
207 #$target->load_components('DB');
208 $target->connection(@info);
215 Matt S. Trout <mst@shadowcatsystems.co.uk>
219 You may distribute this code under the same terms as Perl itself.