1 package DBIx::Class::Schema;
6 use Carp::Clan qw/^DBIx::Class/;
7 use Scalar::Util qw/weaken/;
9 use base qw/DBIx::Class/;
11 __PACKAGE__->mk_classdata('class_mappings' => {});
12 __PACKAGE__->mk_classdata('source_registrations' => {});
13 __PACKAGE__->mk_classdata('storage_type' => '::DBI');
14 __PACKAGE__->mk_classdata('storage');
15 __PACKAGE__->mk_classdata('exception_action');
19 DBIx::Class::Schema - composable schemas
23 package Library::Schema;
24 use base qw/DBIx::Class::Schema/;
26 # load Library::Schema::CD, Library::Schema::Book, Library::Schema::DVD
27 __PACKAGE__->load_classes(qw/CD Book DVD/);
29 package Library::Schema::CD;
30 use base qw/DBIx::Class/;
31 __PACKAGE__->load_components(qw/PK::Auto Core/); # for example
32 __PACKAGE__->table('cd');
34 # Elsewhere in your code:
35 my $schema1 = Library::Schema->connect(
42 my $schema2 = Library::Schema->connect($coderef_returning_dbh);
44 # fetch objects using Library::Schema::DVD
45 my $resultset = $schema1->resultset('DVD')->search( ... );
46 my @dvd_objects = $schema2->resultset('DVD')->search( ... );
50 Creates database classes based on a schema. This is the recommended way to
51 use L<DBIx::Class> and allows you to use more than one concurrent connection
54 NB: If you're used to L<Class::DBI> it's worth reading the L</SYNOPSIS>
55 carefully, as DBIx::Class does things a little differently. Note in
56 particular which module inherits off which.
64 =item Arguments: $moniker, $component_class
68 Registers a class which isa DBIx::Class::ResultSourceProxy. Equivalent to
71 $schema->register_source($moniker, $component_class->result_source_instance);
76 my ($self, $moniker, $to_register) = @_;
77 $self->register_source($moniker => $to_register->result_source_instance);
80 =head2 register_source
84 =item Arguments: $moniker, $result_source
88 Registers the L<DBIx::Class::ResultSource> in the schema with the given
94 my ($self, $moniker, $source) = @_;
95 my %reg = %{$self->source_registrations};
96 $reg{$moniker} = $source;
97 $self->source_registrations(\%reg);
98 $source->schema($self);
99 weaken($source->{schema}) if ref($self);
100 if ($source->result_class) {
101 my %map = %{$self->class_mappings};
102 $map{$source->result_class} = $moniker;
103 $self->class_mappings(\%map);
111 =item Arguments: $moniker
113 =item Return Value: $classname
117 Retrieves the result class name for the given moniker. For example:
119 my $class = $schema->class('CD');
124 my ($self, $moniker) = @_;
125 return $self->source($moniker)->result_class;
132 =item Arguments: $moniker
134 =item Return Value: $result_source
138 my $source = $schema->source('Book');
140 Returns the L<DBIx::Class::ResultSource> object for the registered moniker.
145 my ($self, $moniker) = @_;
146 my $sreg = $self->source_registrations;
147 return $sreg->{$moniker} if exists $sreg->{$moniker};
149 # if we got here, they probably passed a full class name
150 my $mapped = $self->class_mappings->{$moniker};
151 $self->throw_exception("Can't find source for ${moniker}")
152 unless $mapped && exists $sreg->{$mapped};
153 return $sreg->{$mapped};
160 =item Return Value: @source_monikers
164 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?, { $namespace => [ @classes ] }+
202 With no arguments, this method uses L<Module::Find> to find all classes under
203 the schema's namespace. Otherwise, this method loads the classes you specify
204 (using L<use>), and registers them (using L</"register_class">).
206 It is possible to comment out classes with a leading C<#>, but note that perl
207 will think it's a mistake (trying to use a comment in a qw list), so you'll
208 need to add C<no warnings 'qw';> before your load_classes call.
212 My::Schema->load_classes(); # loads My::Schema::CD, My::Schema::Artist,
213 # etc. (anything under the My::Schema namespace)
215 # loads My::Schema::CD, My::Schema::Artist, Other::Namespace::Producer but
216 # not Other::Namespace::LinerNotes nor My::Schema::Track
217 My::Schema->load_classes(qw/ CD Artist #Track /, {
218 Other::Namespace => [qw/ Producer #LinerNotes /],
224 my ($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 $class->ensure_class_loaded($comp_class);
268 $comp_class->source_name($comp) unless $comp_class->source_name;
270 push(@to_register, [ $comp_class->source_name, $comp_class ]);
274 Class::C3->reinitialize;
276 foreach my $to (@to_register) {
277 $class->register_class(@$to);
278 # if $class->can('result_source_instance');
282 =head2 compose_connection
286 =item Arguments: $target_namespace, @db_info
288 =item Return Value: $new_schema
292 Calls L<DBIx::Class::Schema/"compose_namespace"> to the target namespace,
293 calls L<DBIx::Class::Schema/connection> with @db_info on the new schema,
294 then injects the L<DBix::Class::ResultSetProxy> component and a
295 resultset_instance classdata entry on all the new classes, in order to support
296 $target_namespaces::$class->search(...) method calls.
298 This is primarily useful when you have a specific need for class method access
299 to a connection. In normal usage it is preferred to call
300 L<DBIx::Class::Schema/connect> and use the resulting schema object to operate
301 on L<DBIx::Class::ResultSet> objects with L<DBIx::Class::Schema/resultset> for
306 sub compose_connection {
307 my ($self, $target, @info) = @_;
308 my $base = 'DBIx::Class::ResultSetProxy';
309 eval "require ${base};";
310 $self->throw_exception
311 ("No arguments to load_classes and couldn't load ${base} ($@)")
314 if ($self eq $target) {
315 # Pathological case, largely caused by the docs on early C::M::DBIC::Plain
316 foreach my $moniker ($self->sources) {
317 my $source = $self->source($moniker);
318 my $class = $source->result_class;
319 $self->inject_base($class, $base);
320 $class->mk_classdata(resultset_instance => $source->resultset);
321 $class->mk_classdata(class_resolver => $self);
323 $self->connection(@info);
327 my $schema = $self->compose_namespace($target, $base);
330 *{"${target}::schema"} = sub { $schema };
333 $schema->connection(@info);
334 foreach my $moniker ($schema->sources) {
335 my $source = $schema->source($moniker);
336 my $class = $source->result_class;
337 #warn "$moniker $class $source ".$source->storage;
338 $class->mk_classdata(result_source_instance => $source);
339 $class->mk_classdata(resultset_instance => $source->resultset);
340 $class->mk_classdata(class_resolver => $schema);
345 =head2 compose_namespace
349 =item Arguments: $target_namespace, $additional_base_class?
351 =item Return Value: $new_schema
355 For each L<DBIx::Class::ResultSource> in the schema, this method creates a
356 class in the target namespace (e.g. $target_namespace::CD,
357 $target_namespace::Artist) that inherits from the corresponding classes
358 attached to the current schema.
360 It also attaches a corresponding L<DBIx::Class::ResultSource> object to the
361 new $schema object. If C<$additional_base_class> is given, the new composed
362 classes will inherit from first the corresponding classe from the current
363 schema then the base class.
365 For example, for a schema with My::Schema::CD and My::Schema::Artist classes,
367 $schema->compose_namespace('My::DB', 'Base::Class');
368 print join (', ', @My::DB::CD::ISA) . "\n";
369 print join (', ', @My::DB::Artist::ISA) ."\n";
371 will produce the output
373 My::Schema::CD, Base::Class
374 My::Schema::Artist, Base::Class
378 sub compose_namespace {
379 my ($self, $target, $base) = @_;
380 my %reg = %{ $self->source_registrations };
383 my $schema = $self->clone;
385 no warnings qw/redefine/;
386 local *Class::C3::reinitialize = sub { };
387 foreach my $moniker ($schema->sources) {
388 my $source = $schema->source($moniker);
389 my $target_class = "${target}::${moniker}";
391 $target_class => $source->result_class, ($base ? $base : ())
393 $source->result_class($target_class);
394 $target_class->result_source_instance($source)
395 if $target_class->can('result_source_instance');
398 Class::C3->reinitialize();
401 foreach my $meth (qw/class source resultset/) {
402 *{"${target}::${meth}"} =
403 sub { shift->schema->$meth(@_) };
409 =head2 setup_connection_class
413 =item Arguments: $target, @info
417 Sets up a database connection class to inject between the schema and the
418 subclasses that the schema creates.
422 sub setup_connection_class {
423 my ($class, $target, @info) = @_;
424 $class->inject_base($target => 'DBIx::Class::DB');
425 #$target->load_components('DB');
426 $target->connection(@info);
433 =item Arguments: @args
435 =item Return Value: $new_schema
439 Instantiates a new Storage object of type
440 L<DBIx::Class::Schema/"storage_type"> and passes the arguments to
441 $storage->connect_info. Sets the connection in-place on the schema. See
442 L<DBIx::Class::Storage::DBI/"connect_info"> for more information.
447 my ($self, @info) = @_;
448 return $self if !@info && $self->storage;
449 my $storage_class = $self->storage_type;
450 $storage_class = 'DBIx::Class::Storage'.$storage_class
451 if $storage_class =~ m/^::/;
452 eval "require ${storage_class};";
453 $self->throw_exception(
454 "No arguments to load_classes and couldn't load ${storage_class} ($@)"
456 my $storage = $storage_class->new($self);
457 $storage->connect_info(\@info);
458 $self->storage($storage);
466 =item Arguments: @info
468 =item Return Value: $new_schema
472 This is a convenience method. It is equivalent to calling
473 $schema->clone->connection(@info). See L</connection> and L</clone> for more
478 sub connect { shift->clone->connection(@_) }
482 Begins a transaction (does nothing if AutoCommit is off). Equivalent to
483 calling $schema->storage->txn_begin. See
484 L<DBIx::Class::Storage::DBI/"txn_begin"> for more information.
488 sub txn_begin { shift->storage->txn_begin }
492 Commits the current transaction. Equivalent to calling
493 $schema->storage->txn_commit. See L<DBIx::Class::Storage::DBI/"txn_commit">
494 for more information.
498 sub txn_commit { shift->storage->txn_commit }
502 Rolls back the current transaction. Equivalent to calling
503 $schema->storage->txn_rollback. See
504 L<DBIx::Class::Storage::DBI/"txn_rollback"> for more information.
508 sub txn_rollback { shift->storage->txn_rollback }
514 =item Arguments: C<$coderef>, @coderef_args?
516 =item Return Value: The return value of $coderef
520 Executes C<$coderef> with (optional) arguments C<@coderef_args> atomically,
521 returning its result (if any). If an exception is caught, a rollback is issued
522 and the exception is rethrown. If the rollback fails, (i.e. throws an
523 exception) an exception is thrown that includes a "Rollback failed" message.
527 my $author_rs = $schema->resultset('Author')->find(1);
528 my @titles = qw/Night Day It/;
531 # If any one of these fails, the entire transaction fails
532 $author_rs->create_related('books', {
534 }) foreach (@titles);
536 return $author->books;
541 $rs = $schema->txn_do($coderef);
544 if ($@) { # Transaction failed
545 die "something terrible has happened!" #
546 if ($@ =~ /Rollback failed/); # Rollback failed
548 deal_with_failed_transaction();
551 In a nested transaction (calling txn_do() from within a txn_do() coderef) only
552 the outermost transaction will issue a L<DBIx::Class::Schema/"txn_commit"> on
553 the Schema's storage, and txn_do() can be called in void, scalar and list
554 context and it will behave as expected.
559 my ($self, $coderef, @args) = @_;
561 $self->storage or $self->throw_exception
562 ('txn_do called on $schema without storage');
563 ref $coderef eq 'CODE' or $self->throw_exception
564 ('$coderef must be a CODE reference');
566 my (@return_values, $return_value);
568 $self->txn_begin; # If this throws an exception, no rollback is needed
570 my $wantarray = wantarray; # Need to save this since the context
571 # inside the eval{} block is independent
572 # of the context that called txn_do()
575 # Need to differentiate between scalar/list context to allow for
576 # returning a list in scalar context to get the size of the list
579 @return_values = $coderef->(@args);
580 } elsif (defined $wantarray) {
582 $return_value = $coderef->(@args);
598 my $rollback_error = $@;
599 my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION";
600 $self->throw_exception($error) # propagate nested rollback
601 if $rollback_error =~ /$exception_class/;
603 $self->throw_exception(
604 "Transaction aborted: $error. Rollback failed: ${rollback_error}"
607 $self->throw_exception($error); # txn failed but rollback succeeded
611 return $wantarray ? @return_values : $return_value;
618 =item Return Value: $new_schema
622 Clones the schema and its associated result_source objects and returns the
629 my $clone = bless({ (ref $self ? %$self : ()) }, ref $self || $self);
630 foreach my $moniker ($self->sources) {
631 my $source = $self->source($moniker);
632 my $new = $source->new($source);
633 $clone->register_source($moniker => $new);
635 $clone->storage->set_schema($clone) if $clone->storage;
643 =item Arguments: $moniker, \@data;
647 Populates the source registered with the given moniker with the supplied data.
648 @data should be a list of listrefs -- the first containing column names, the
649 second matching values.
653 $schema->populate('Artist', [
654 [ qw/artistid name/ ],
655 [ 1, 'Popular Band' ],
663 my ($self, $name, $data) = @_;
664 my $rs = $self->resultset($name);
665 my @names = @{shift(@$data)};
667 foreach my $item (@$data) {
669 @create{@names} = @$item;
670 push(@created, $rs->create(\%create));
675 =head2 exception_action
679 =item Arguments: $code_reference
683 If C<exception_action> is set for this class/object, L</throw_exception>
684 will prefer to call this code reference with the exception as an argument,
685 rather than its normal <croak> action.
687 Your subroutine should probably just wrap the error in the exception
688 object/class of your choosing and rethrow. If, against all sage advice,
689 you'd like your C<exception_action> to suppress a particular exception
690 completely, simply have it return true.
695 use base qw/DBIx::Class::Schema/;
696 use My::ExceptionClass;
697 __PACKAGE__->exception_action(sub { My::ExceptionClass->throw(@_) });
698 __PACKAGE__->load_classes;
701 my $schema_obj = My::Schema->connect( .... );
702 $schema_obj->exception_action(sub { My::ExceptionClass->throw(@_) });
704 # suppress all exceptions, like a moron:
705 $schema_obj->exception_action(sub { 1 });
707 =head2 throw_exception
711 =item Arguments: $message
715 Throws an exception. Defaults to using L<Carp::Clan> to report errors from
716 user's perspective. See L</exception_action> for details on overriding
717 this method's behavior.
721 sub throw_exception {
723 croak @_ if !$self->exception_action || !$self->exception_action->(@_);
726 =head2 deploy (EXPERIMENTAL)
730 =item Arguments: $sqlt_args
734 Attempts to deploy the schema to the current storage using L<SQL::Translator>.
736 Note that this feature is currently EXPERIMENTAL and may not work correctly
737 across all databases, or fully handle complex relationships.
739 See L<SQL::Translator/METHODS> for a list of values for C<$sqlt_args>. The most
740 common value for this would be C<< { add_drop_table => 1, } >> to have the SQL
741 produced include a DROP TABLE statement for each table created.
746 my ($self, $sqltargs) = @_;
747 $self->throw_exception("Can't deploy without storage") unless $self->storage;
748 $self->storage->deploy($self, undef, $sqltargs);
751 =head2 create_ddl_dir (EXPERIMENTAL)
755 =item Arguments: \@databases, $version, $directory, $sqlt_args
759 Creates an SQL file based on the Schema, for each of the specified
760 database types, in the given directory.
762 Note that this feature is currently EXPERIMENTAL and may not work correctly
763 across all databases, or fully handle complex relationships.
771 $self->throw_exception("Can't create_ddl_dir without storage") unless $self->storage;
772 $self->storage->create_ddl_dir($self, @_);
775 =head2 ddl_filename (EXPERIMENTAL)
777 my $filename = $table->ddl_filename($type, $dir, $version)
779 Creates a filename for a SQL file based on the table class name. Not
780 intended for direct end user use.
786 my ($self, $type, $dir, $version) = @_;
788 my $filename = ref($self);
789 $filename =~ s/::/-/;
790 $filename = "$dir$filename-$version-$type.sql";
799 Matt S. Trout <mst@shadowcatsystems.co.uk>
803 You may distribute this code under the same terms as Perl itself.