1 package DBIx::Class::Schema;
6 use Carp::Clan qw/^DBIx::Class/;
8 use base qw/DBIx::Class/;
10 __PACKAGE__->mk_classdata('class_mappings' => {});
11 __PACKAGE__->mk_classdata('source_registrations' => {});
12 __PACKAGE__->mk_classdata('storage_type' => '::DBI');
13 __PACKAGE__->mk_classdata('storage');
17 DBIx::Class::Schema - composable schemas
21 package Library::Schema;
22 use base qw/DBIx::Class::Schema/;
24 # load Library::Schema::CD, Library::Schema::Book, Library::Schema::DVD
25 __PACKAGE__->load_classes(qw/CD Book DVD/);
27 package Library::Schema::CD;
28 use base qw/DBIx::Class/;
29 __PACKAGE__->load_components(qw/PK::Auto Core/); # for example
30 __PACKAGE__->table('cd');
32 # Elsewhere in your code:
33 my $schema1 = Library::Schema->connect(
40 my $schema2 = Library::Schema->connect($coderef_returning_dbh);
42 # fetch objects using Library::Schema::DVD
43 my $resultset = $schema1->resultset('DVD')->search( ... );
44 my @dvd_objects = $schema2->resultset('DVD')->search( ... );
48 Creates database classes based on a schema. This is the recommended way to
49 use L<DBIx::Class> and allows you to use more than one concurrent connection
52 NB: If you're used to L<Class::DBI> it's worth reading the L</SYNOPSIS>
53 carefully as DBIx::Class does things a little differently. Note in
54 particular which module inherits off which.
62 =item Arguments: $moniker, $component_class
66 Registers a class which isa L<DBIx::Class::ResultSourceProxy>. Equivalent to
69 $schema->register_source($moniker, $component_class->result_source_instance);
74 my ($self, $moniker, $to_register) = @_;
75 $self->register_source($moniker => $to_register->result_source_instance);
78 =head2 register_source
82 =item Arguments: $moniker, $result_source
86 Registers the L<DBIx::Class::ResultSource> in the schema with the given
92 my ($self, $moniker, $source) = @_;
93 my %reg = %{$self->source_registrations};
94 $reg{$moniker} = $source;
95 $self->source_registrations(\%reg);
96 $source->schema($self);
97 if ($source->result_class) {
98 my %map = %{$self->class_mappings};
99 $map{$source->result_class} = $moniker;
100 $self->class_mappings(\%map);
108 =item Arguments: $moniker
110 =item Return Value: $classname
114 Retrieves the result class name for the given moniker.
118 my $class = $schema->class('CD');
123 my ($self, $moniker) = @_;
124 return $self->source($moniker)->result_class;
131 =item Arguments: $moniker
133 =item Return Value: $result_source
137 my $source = $schema->source('Book');
139 Returns the L<DBIx::Class::ResultSource> object for the registered moniker.
144 my ($self, $moniker) = @_;
145 my $sreg = $self->source_registrations;
146 return $sreg->{$moniker} if exists $sreg->{$moniker};
148 # if we got here, they probably passed a full class name
149 my $mapped = $self->class_mappings->{$moniker};
150 $self->throw_exception("Can't find source for ${moniker}")
151 unless $mapped && exists $sreg->{$mapped};
152 return $sreg->{$mapped};
159 =item Return Value: @source_monikers
163 Returns the source monikers of all source registrations on this schema.
167 my @source_monikers = $schema->sources;
171 sub sources { return keys %{shift->source_registrations}; }
177 =item Arguments: $moniker
179 =item Return Value: $result_set
183 my $rs = $schema->resultset('DVD');
185 Returns the L<DBIx::Class::ResultSet> object for the registered moniker.
190 my ($self, $moniker) = @_;
191 return $self->source($moniker)->resultset;
198 =item Arguments: @classes?, { $namespace => [ @classes ] }+
202 With no arguments, this method uses L<Module::Find> to find all classes under
203 the schema's namespace. Otherwise, this method loads the classes you specify
204 (using L<use>), and registers them (using L</"register_class">).
206 It is possible to comment out classes with a leading '#', but note that perl
207 will think it's a mistake (trying to use a comment in a qw list) so you'll
208 need to add "no warnings 'qw';" before your load_classes call.
212 My::Schema->load_classes(); # loads My::Schema::CD, My::Schema::Artist,
213 # etc. (anything under the My::Schema namespace)
215 # loads My::Schema::CD, My::Schema::Artist, Other::Namespace::Producer but
216 # not Other::Namespace::LinerNotes nor My::Schema::Track
217 My::Schema->load_classes(qw/ CD Artist #Track /, {
218 Other::Namespace => [qw/ Producer #LinerNotes /],
224 my ($class, @params) = @_;
229 foreach my $param (@params) {
230 if (ref $param eq 'ARRAY') {
231 # filter out commented entries
232 my @modules = grep { $_ !~ /^#/ } @$param;
234 push (@{$comps_for{$class}}, @modules);
236 elsif (ref $param eq 'HASH') {
237 # more than one namespace possible
238 for my $comp ( keys %$param ) {
239 # filter out commented entries
240 my @modules = grep { $_ !~ /^#/ } @{$param->{$comp}};
242 push (@{$comps_for{$comp}}, @modules);
246 # filter out commented entries
247 push (@{$comps_for{$class}}, $param) if $param !~ /^#/;
251 eval "require Module::Find;";
252 $class->throw_exception(
253 "No arguments to load_classes and couldn't load Module::Find ($@)"
255 my @comp = map { substr $_, length "${class}::" }
256 Module::Find::findallmod($class);
257 $comps_for{$class} = \@comp;
262 no warnings qw/redefine/;
263 local *Class::C3::reinitialize = sub { };
264 foreach my $prefix (keys %comps_for) {
265 foreach my $comp (@{$comps_for{$prefix}||[]}) {
266 my $comp_class = "${prefix}::${comp}";
267 eval "use $comp_class"; # If it fails, assume the user fixed it
269 $comp_class =~ s/::/\//g;
270 die $@ unless $@ =~ /Can't locate.+$comp_class\.pm\sin\s\@INC/;
273 push(@to_register, [ $comp, $comp_class ]);
277 Class::C3->reinitialize;
279 foreach my $to (@to_register) {
280 $class->register_class(@$to);
281 # if $class->can('result_source_instance');
285 =head2 compose_connection
289 =item Arguments: $target_namespace, @db_info
291 =item Return Value: $new_schema
295 Calls L<DBIx::Class::schema/"compose_namespace"> to the target namespace,
296 calls L<DBIx::Class::Schema/connection>(@db_info) on the new schema, then
297 injects the L<DBix::Class::ResultSetProxy> component and a resultset_instance
298 classdata entry on all the new classes in order to support
299 $target_namespaces::$class->search(...) method calls.
301 This is primarily useful when you have a specific need for class method access
302 to a connection. In normal usage it is preferred to call
303 L<DBIx::Class::Schema/connect> and use the resulting schema object to operate
304 on L<DBIx::Class::ResultSet> objects with L<DBIx::Class::Schema/resultset> for
309 sub compose_connection {
310 my ($self, $target, @info) = @_;
311 my $base = 'DBIx::Class::ResultSetProxy';
312 eval "require ${base};";
313 $self->throw_exception
314 ("No arguments to load_classes and couldn't load ${base} ($@)")
317 if ($self eq $target) {
318 # Pathological case, largely caused by the docs on early C::M::DBIC::Plain
319 foreach my $moniker ($self->sources) {
320 my $source = $self->source($moniker);
321 my $class = $source->result_class;
322 $self->inject_base($class, $base);
323 $class->mk_classdata(resultset_instance => $source->resultset);
324 $class->mk_classdata(class_resolver => $self);
326 $self->connection(@info);
330 my $schema = $self->compose_namespace($target, $base);
333 *{"${target}::schema"} = sub { $schema };
336 $schema->connection(@info);
337 foreach my $moniker ($schema->sources) {
338 my $source = $schema->source($moniker);
339 my $class = $source->result_class;
340 #warn "$moniker $class $source ".$source->storage;
341 $class->mk_classdata(result_source_instance => $source);
342 $class->mk_classdata(resultset_instance => $source->resultset);
343 $class->mk_classdata(class_resolver => $schema);
348 =head2 compose_namespace
352 =item Arguments: $target_namespace, $additional_base_class?
354 =item Return Value: $new_schema
358 For each L<DBIx::Class::ResultSource> in the schema, this method creates a
359 class in the target namespace (e.g. $target_namespace::CD,
360 $target_namespace::Artist) that inherits from the corresponding classes
361 attached to the current schema.
363 It also attaches a corresponding L<DBIx::Class::ResultSource> object to the
364 new $schema object. If C<$additional_base_class> is given, the new composed
365 classes will inherit from first the corresponding classe from the current
366 schema then the base class.
368 e.g. (for a schema with My::Schema::CD and My::Schema::Artist classes),
370 $schema->compose_namespace('My::DB', 'Base::Class');
371 print join (', ', @My::DB::CD::ISA) . "\n";
372 print join (', ', @My::DB::Artist::ISA) ."\n";
374 Will produce the output
376 My::Schema::CD, Base::Class
377 My::Schema::Artist, Base::Class
381 sub compose_namespace {
382 my ($self, $target, $base) = @_;
383 my %reg = %{ $self->source_registrations };
386 my $schema = $self->clone;
388 no warnings qw/redefine/;
389 local *Class::C3::reinitialize = sub { };
390 foreach my $moniker ($schema->sources) {
391 my $source = $schema->source($moniker);
392 my $target_class = "${target}::${moniker}";
394 $target_class => $source->result_class, ($base ? $base : ())
396 $source->result_class($target_class);
399 Class::C3->reinitialize();
402 foreach my $meth (qw/class source resultset/) {
403 *{"${target}::${meth}"} =
404 sub { shift->schema->$meth(@_) };
410 =head2 setup_connection_class
414 =item Arguments: $target, @info
418 Sets up a database connection class to inject between the schema and the
419 subclasses that the schema creates.
423 sub setup_connection_class {
424 my ($class, $target, @info) = @_;
425 $class->inject_base($target => 'DBIx::Class::DB');
426 #$target->load_components('DB');
427 $target->connection(@info);
434 =item Arguments: @args
436 =item Return Value: $new_schema
440 Instantiates a new Storage object of type
441 L<DBIx::Class::Schema/"storage_type"> and passes the arguments to
442 $storage->connect_info. Sets the connection in-place on the schema. See
443 L<DBIx::Class::Storage::DBI/"connect_info"> for more information.
448 my ($self, @info) = @_;
449 return $self if !@info && $self->storage;
450 my $storage_class = $self->storage_type;
451 $storage_class = 'DBIx::Class::Storage'.$storage_class
452 if $storage_class =~ m/^::/;
453 eval "require ${storage_class};";
454 $self->throw_exception(
455 "No arguments to load_classes and couldn't load ${storage_class} ($@)"
457 my $storage = $storage_class->new;
458 $storage->connect_info(\@info);
459 $self->storage($storage);
467 =item Arguments: @info
469 =item Return Value: $new_schema
473 This is a convenience method. It is equivalent to calling
474 $schema->clone->connection(@info). See L</connection> and L</clone> for more
479 sub connect { shift->clone->connection(@_) }
483 Begins a transaction (does nothing if AutoCommit is off). Equivalent to
484 calling $schema->storage->txn_begin. See
485 L<DBIx::Class::Storage::DBI/"txn_begin"> for more information.
489 sub txn_begin { shift->storage->txn_begin }
493 Commits the current transaction. Equivalent to calling
494 $schema->storage->txn_commit. See L<DBIx::Class::Storage::DBI/"txn_commit">
495 for more information.
499 sub txn_commit { shift->storage->txn_commit }
503 Rolls back the current transaction. Equivalent to calling
504 $schema->storage->txn_rollback. See
505 L<DBIx::Class::Storage::DBI/"txn_rollback"> for more information.
509 sub txn_rollback { shift->storage->txn_rollback }
515 =item Arguments: C<$coderef>, @coderef_args?
517 =item Return Value: The return value of $coderef
521 Executes C<$coderef> with (optional) arguments C<@coderef_args> atomically,
522 returning its result (if any). If an exception is caught, a rollback is issued
523 and the exception is rethrown. If the rollback fails, (i.e. throws an
524 exception) an exception is thrown that includes a "Rollback failed" message.
528 my $author_rs = $schema->resultset('Author')->find(1);
531 my ($author, @titles) = @_;
533 # If any one of these fails, the entire transaction fails
534 $author->create_related('books', {
536 }) foreach (@titles);
538 return $author->books;
543 $rs = $schema->txn_do($coderef, $author_rs, qw/Night Day It/);
548 if ($error =~ /Rollback failed/) {
549 die "something terrible has happened!";
551 deal_with_failed_transaction();
555 In a nested transaction (calling txn_do() from within a txn_do() coderef) only
556 the outermost transaction will issue a L<DBIx::Class::Schema/"txn_commit"> on
557 the Schema's storage, and txn_do() can be called in void, scalar and list
558 context and it will behave as expected.
563 my ($self, $coderef, @args) = @_;
565 ref $self or $self->throw_exception
566 ('Cannot execute txn_do as a class method');
567 ref $coderef eq 'CODE' or $self->throw_exception
568 ('$coderef must be a CODE reference');
570 my (@return_values, $return_value);
572 $self->txn_begin; # If this throws an exception, no rollback is needed
574 my $wantarray = wantarray; # Need to save this since the context
575 # inside the eval{} block is independent
576 # of the context that called txn_do()
579 # Need to differentiate between scalar/list context to allow for
580 # returning a list in scalar context to get the size of the list
583 @return_values = $coderef->(@args);
584 } elsif (defined $wantarray) {
586 $return_value = $coderef->(@args);
602 my $rollback_error = $@;
603 my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION";
604 $self->throw_exception($error) # propagate nested rollback
605 if $rollback_error =~ /$exception_class/;
607 $self->throw_exception(
608 "Transaction aborted: $error. Rollback failed: ${rollback_error}"
611 $self->throw_exception($error); # txn failed but rollback succeeded
615 return $wantarray ? @return_values : $return_value;
622 =item Return Value: $new_schema
626 Clones the schema and its associated result_source objects and returns the
633 my $clone = bless({ (ref $self ? %$self : ()) }, ref $self || $self);
634 foreach my $moniker ($self->sources) {
635 my $source = $self->source($moniker);
636 my $new = $source->new($source);
637 $clone->register_source($moniker => $new);
646 =item Arguments: $moniker, \@data;
650 Populates the source registered with the given moniker with the supplied data.
651 @data should be a list of listrefs -- the first containing column names, the
652 second matching values.
656 $schema->populate('Artist', [
657 [ qw/artistid name/ ],
658 [ 1, 'Popular Band' ],
666 my ($self, $name, $data) = @_;
667 my $rs = $self->resultset($name);
668 my @names = @{shift(@$data)};
670 foreach my $item (@$data) {
672 @create{@names} = @$item;
673 push(@created, $rs->create(\%create));
678 =head2 throw_exception
682 =item Arguments: $message
686 Throws an exception. Defaults to using L<Carp::Clan> to report errors from
691 sub throw_exception {
696 =head2 deploy (EXPERIMENTAL)
700 =item Arguments: $sqlt_args
704 Attempts to deploy the schema to the current storage using L<SQL::Translator>.
706 Note that this feature is currently EXPERIMENTAL and may not work correctly
707 across all databases, or fully handle complex relationships.
712 my ($self, $sqltargs) = @_;
713 $self->throw_exception("Can't deploy without storage") unless $self->storage;
714 $self->storage->deploy($self, undef, $sqltargs);
721 Matt S. Trout <mst@shadowcatsystems.co.uk>
725 You may distribute this code under the same terms as Perl itself.