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};
90 my $class = $schema->class('Foo');
92 Shortcut to retrieve a single class by its registered name
97 my ($self, $class) = @_;
98 return $self->class_registrations->{$class};
101 =head2 load_classes [<classes>, (<class>, <class>), {<namespace> => [<classes>]}]
103 Uses L<Module::Find> to find all classes under the database class' namespace,
104 or uses the classes you select. Then it loads the component (using L<use>),
105 and registers them (using B<register_class>);
107 It is possible to comment out classes with a leading '#', but note that perl
108 will think it's a mistake (trying to use a comment in a qw list) so you'll
109 need to add "no warnings 'qw';" before your load_classes call.
114 my ($class, @params) = @_;
119 foreach my $param (@params) {
120 if (ref $param eq 'ARRAY') {
121 # filter out commented entries
122 my @modules = grep { $_ !~ /^#/ } @$param;
124 push (@{$comps_for{$class}}, @modules);
126 elsif (ref $param eq 'HASH') {
127 # more than one namespace possible
128 for my $comp ( keys %$param ) {
129 # filter out commented entries
130 my @modules = grep { $_ !~ /^#/ } @{$param->{$comp}};
132 push (@{$comps_for{$comp}}, @modules);
136 # filter out commented entries
137 push (@{$comps_for{$class}}, $param) if $param !~ /^#/;
141 eval "require Module::Find;";
142 $class->throw("No arguments to load_classes and couldn't load".
143 " Module::Find ($@)") if $@;
144 my @comp = map { substr $_, length "${class}::" } Module::Find::findallmod($class);
145 $comps_for{$class} = \@comp;
148 foreach my $prefix (keys %comps_for) {
149 foreach my $comp (@{$comps_for{$prefix}||[]}) {
150 my $comp_class = "${prefix}::${comp}";
151 eval "use $comp_class"; # If it fails, assume the user fixed it
153 die $@ unless $@ =~ /Can't locate/;
155 $class->register_class($comp => $comp_class);
160 =head2 compose_connection <target> <@db_info>
162 This is the most important method in this class. it takes a target namespace,
163 as well as dbh connection info, and creates a L<DBIx::Class::DB> class as
164 well as subclasses for each of your database classes in this namespace, using
167 It will also setup a ->class method on the target class, which lets you
168 resolve database classes based on the schema component name, for example
170 MyApp::DB->class('Foo') # returns MyApp::DB::Foo,
171 # which ISA MyApp::Schema::Foo
173 This is the recommended API for accessing Schema generated classes, and
174 using it might give you instant advantages with future versions of DBIC.
176 WARNING: Loading components into Schema classes after compose_connection
177 may not cause them to be seen by the classes in your target namespace due
178 to the dispatch table approach used by Class::C3. If you do this you may find
179 you need to call Class::C3->reinitialize() afterwards to get the behaviour
184 sub compose_connection {
185 my ($class, $target, @info) = @_;
186 my $conn_class = "${target}::_db";
187 $class->setup_connection_class($conn_class, @info);
188 my $schema = $class->compose_namespace($target, $conn_class);
189 $schema->storage($conn_class->storage);
190 foreach my $class ($schema->registered_classes) {
191 my $source = $class->result_source;
192 $source = $source->new($source);
193 $source->schema($schema);
194 $source->result_class($class);
195 $class->mk_classdata(result_source => $source);
200 sub compose_namespace {
201 my ($class, $target, $base) = @_;
202 my %reg = %{ $class->class_registrations };
205 my $schema = bless({ }, $class);
206 while (my ($comp, $comp_class) = each %reg) {
207 my $target_class = "${target}::${comp}";
208 $class->inject_base($target_class, $comp_class, $base);
209 @map{$comp, $comp_class} = ($target_class, $target_class);
211 $schema->class_registrations(\%map);
214 *{"${target}::schema"} =
216 *{"${target}::class"} =
217 sub { shift->schema->class(@_) };
219 $base->class_resolver($target);
223 =head2 setup_connection_class <$target> <@info>
225 Sets up a database connection class to inject between the schema
226 and the subclasses the schema creates.
230 sub setup_connection_class {
231 my ($class, $target, @info) = @_;
232 $class->inject_base($target => 'DBIx::Class::DB');
233 #$target->load_components('DB');
234 $target->connection(@info);
241 Matt S. Trout <mst@shadowcatsystems.co.uk>
245 You may distribute this code under the same terms as Perl itself.