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::Pg 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.
60 =head3 Arguments: <moniker> <component_class>
62 Registers a class which isa ResultSourceProxy; equivalent to calling
64 $schema->register_source($moniker, $component_class->result_source_instance);
69 my ($self, $moniker, $to_register) = @_;
70 $self->register_source($moniker => $to_register->result_source_instance);
73 =head2 register_source
75 =head3 Arguments: <moniker> <result source>
77 Registers the result source in the schema with the given moniker
82 my ($self, $moniker, $source) = @_;
83 my %reg = %{$self->source_registrations};
84 $reg{$moniker} = $source;
85 $self->source_registrations(\%reg);
86 $source->schema($self);
87 if ($source->result_class) {
88 my %map = %{$self->class_mappings};
89 $map{$source->result_class} = $moniker;
90 $self->class_mappings(\%map);
96 my $class = $schema->class('CD');
98 Retrieves the result class name for a given result source
103 my ($self, $moniker) = @_;
104 return $self->source($moniker)->result_class;
109 my $source = $schema->source('Book');
111 Returns the result source object for the registered name
116 my ($self, $moniker) = @_;
117 my $sreg = $self->source_registrations;
118 return $sreg->{$moniker} if exists $sreg->{$moniker};
120 # if we got here, they probably passed a full class name
121 my $mapped = $self->class_mappings->{$moniker};
122 $self->throw_exception("Can't find source for ${moniker}")
123 unless $mapped && exists $sreg->{$mapped};
124 return $sreg->{$mapped};
129 my @source_monikers = $schema->sources;
131 Returns the source monikers of all source registrations on this schema
135 sub sources { return keys %{shift->source_registrations}; }
139 my $rs = $schema->resultset('DVD');
141 Returns the resultset for the registered moniker
146 my ($self, $moniker) = @_;
147 return $self->source($moniker)->resultset;
152 =head3 Arguments: [<classes>, (<class>, <class>), {<namespace> => [<classes>]}]
154 Uses L<Module::Find> to find all classes under the database class' namespace,
155 or uses the classes you select. Then it loads the component (using L<use>),
156 and registers them (using B<register_class>);
158 It is possible to comment out classes with a leading '#', but note that perl
159 will think it's a mistake (trying to use a comment in a qw list) so you'll
160 need to add "no warnings 'qw';" before your load_classes call.
165 my ($class, @params) = @_;
170 foreach my $param (@params) {
171 if (ref $param eq 'ARRAY') {
172 # filter out commented entries
173 my @modules = grep { $_ !~ /^#/ } @$param;
175 push (@{$comps_for{$class}}, @modules);
177 elsif (ref $param eq 'HASH') {
178 # more than one namespace possible
179 for my $comp ( keys %$param ) {
180 # filter out commented entries
181 my @modules = grep { $_ !~ /^#/ } @{$param->{$comp}};
183 push (@{$comps_for{$comp}}, @modules);
187 # filter out commented entries
188 push (@{$comps_for{$class}}, $param) if $param !~ /^#/;
192 eval "require Module::Find;";
193 $class->throw_exception("No arguments to load_classes and couldn't load".
194 " Module::Find ($@)") if $@;
195 my @comp = map { substr $_, length "${class}::" } Module::Find::findallmod($class);
196 $comps_for{$class} = \@comp;
201 no warnings qw/redefine/;
202 local *Class::C3::reinitialize = sub { };
203 foreach my $prefix (keys %comps_for) {
204 foreach my $comp (@{$comps_for{$prefix}||[]}) {
205 my $comp_class = "${prefix}::${comp}";
206 eval "use $comp_class"; # If it fails, assume the user fixed it
208 $comp_class =~ s/::/\//g;
209 die $@ unless $@ =~ /Can't locate.+$comp_class\.pm\sin\s\@INC/;
212 push(@to_register, [ $comp, $comp_class ]);
216 Class::C3->reinitialize;
218 foreach my $to (@to_register) {
219 $class->register_class(@$to);
220 # if $class->can('result_source_instance');
224 =head2 compose_connection
226 =head3 Arguments: <target> <@db_info>
228 This is the most important method in this class. it takes a target namespace,
229 as well as dbh connection info, and creates a L<DBIx::Class::DB> class as
230 well as subclasses for each of your database classes in this namespace, using
233 It will also setup a ->class method on the target class, which lets you
234 resolve database classes based on the schema component name, for example
236 Library::Model::DB->class('Book') # returns Library::Model::Book,
237 # which ISA Library::Schema::Book
239 This is the recommended API for accessing Schema generated classes, and
240 using it might give you instant advantages with future versions of DBIC.
242 WARNING: Loading components into Schema classes after compose_connection
243 may not cause them to be seen by the classes in your target namespace due
244 to the dispatch table approach used by Class::C3. If you do this you may find
245 you need to call Class::C3->reinitialize() afterwards to get the behaviour
250 sub compose_connection {
251 my ($self, $target, @info) = @_;
252 my $base = 'DBIx::Class::ResultSetProxy';
253 eval "require ${base};";
254 $self->throw_exception("No arguments to load_classes and couldn't load".
255 " ${base} ($@)") if $@;
257 if ($self eq $target) {
258 # Pathological case, largely caused by the docs on early C::M::DBIC::Plain
259 foreach my $moniker ($self->sources) {
260 my $source = $self->source($moniker);
261 my $class = $source->result_class;
262 $self->inject_base($class, $base);
263 $class->mk_classdata(resultset_instance => $source->resultset);
264 $class->mk_classdata(class_resolver => $self);
266 $self->connection(@info);
270 my $schema = $self->compose_namespace($target, $base);
273 *{"${target}::schema"} = sub { $schema };
276 $schema->connection(@info);
277 foreach my $moniker ($schema->sources) {
278 my $source = $schema->source($moniker);
279 my $class = $source->result_class;
280 #warn "$moniker $class $source ".$source->storage;
281 $class->mk_classdata(result_source_instance => $source);
282 $class->mk_classdata(resultset_instance => $source->resultset);
283 $class->mk_classdata(class_resolver => $schema);
288 sub compose_namespace {
289 my ($self, $target, $base) = @_;
290 my %reg = %{ $self->source_registrations };
293 my $schema = $self->clone;
295 no warnings qw/redefine/;
296 local *Class::C3::reinitialize = sub { };
297 foreach my $moniker ($schema->sources) {
298 my $source = $schema->source($moniker);
299 my $target_class = "${target}::${moniker}";
301 $target_class => $source->result_class, ($base ? $base : ())
303 $source->result_class($target_class);
306 Class::C3->reinitialize();
309 foreach my $meth (qw/class source resultset/) {
310 *{"${target}::${meth}"} =
311 sub { shift->schema->$meth(@_) };
317 =head2 setup_connection_class
319 =head3 Arguments: <$target> <@info>
321 Sets up a database connection class to inject between the schema
322 and the subclasses the schema creates.
326 sub setup_connection_class {
327 my ($class, $target, @info) = @_;
328 $class->inject_base($target => 'DBIx::Class::DB');
329 #$target->load_components('DB');
330 $target->connection(@info);
335 =head3 Arguments: (@args)
337 Instantiates a new Storage object of type storage_type and passes the
338 arguments to $storage->connect_info. Sets the connection in-place on
344 my ($self, @info) = @_;
345 return $self if !@info && $self->storage;
346 my $storage_class = $self->storage_type;
347 $storage_class = 'DBIx::Class::Storage'.$storage_class
348 if $storage_class =~ m/^::/;
349 eval "require ${storage_class};";
350 $self->throw_exception("No arguments to load_classes and couldn't load".
351 " ${storage_class} ($@)") if $@;
352 my $storage = $storage_class->new;
353 $storage->connect_info(\@info);
354 $self->storage($storage);
360 =head3 Arguments: (@info)
362 Conveneience method, equivalent to $schema->clone->connection(@info)
366 sub connect { shift->clone->connection(@_) }
370 Begins a transaction (does nothing if AutoCommit is off).
374 sub txn_begin { shift->storage->txn_begin }
378 Commits the current transaction.
382 sub txn_commit { shift->storage->txn_commit }
386 Rolls back the current transaction.
390 sub txn_rollback { shift->storage->txn_rollback }
394 =head3 Arguments: <$coderef>, [@coderef_args]
396 Executes C<$coderef> with (optional) arguments C<@coderef_args>
397 transactionally, returning its result (if any). If an exception is
398 caught, a rollback is issued and the exception is rethrown. If the
399 rollback fails, (i.e. throws an exception) an exception is thrown that
400 includes a "Rollback failed" message.
404 my $author_rs = $schema->resultset('Author')->find(1);
407 my ($author, @titles) = @_;
409 # If any one of these fails, the entire transaction fails
410 $author->create_related('books', {
412 }) foreach (@titles);
414 return $author->books;
419 $rs = $schema->txn_do($coderef, $author_rs, qw/Night Day It/);
424 if ($error =~ /Rollback failed/) {
425 die "something terrible has happened!";
427 deal_with_failed_transaction();
431 Nested transactions work as expected (i.e. only the outermost
432 transaction will issue a txn_commit on the Schema's storage), and
433 txn_do() can be called in void, scalar and list context and it will
439 my ($self, $coderef, @args) = @_;
441 ref $self or $self->throw_exception
442 ('Cannot execute txn_do as a class method');
443 ref $coderef eq 'CODE' or $self->throw_exception
444 ('$coderef must be a CODE reference');
446 my (@return_values, $return_value);
448 $self->txn_begin; # If this throws an exception, no rollback is needed
450 my $wantarray = wantarray; # Need to save this since it's reset in eval{}
453 # Need to differentiate between scalar/list context to allow for
454 # returning a list in scalar context to get the size of the list
458 @return_values = $coderef->(@args);
459 } elsif (defined $wantarray) {
461 $return_value = $coderef->(@args);
477 my $rollback_error = $@;
478 my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION";
479 $self->throw_exception($error) # propagate nested rollback
480 if $rollback_error =~ /$exception_class/;
482 $self->throw_exception("Transaction aborted: $error. Rollback failed: ".
485 $self->throw_exception($error); # txn failed but rollback succeeded
489 return $wantarray ? @return_values : $return_value;
494 Clones the schema and its associated result_source objects and returns the
501 my $clone = bless({ (ref $self ? %$self : ()) }, ref $self || $self);
502 foreach my $moniker ($self->sources) {
503 my $source = $self->source($moniker);
504 my $new = $source->new($source);
505 $clone->register_source($moniker => $new);
512 =head3 Arguments: ($moniker, \@data);
514 Populates the source registered with the given moniker with the supplied data.
515 @data should be a list of listrefs, the first containing column names, the
516 second matching values - i.e.
518 $schema->populate('Artist', [
519 [ qw/artistid name/ ],
520 [ 1, 'Popular Band' ],
528 my ($self, $name, $data) = @_;
529 my $rs = $self->resultset($name);
530 my @names = @{shift(@$data)};
532 foreach my $item (@$data) {
534 @create{@names} = @$item;
535 push(@created, $rs->create(\%create));
540 =head2 throw_exception
542 Defaults to using Carp::Clan to report errors from user perspective.
546 sub throw_exception {
551 =head2 deploy (EXPERIMENTAL)
553 Attempts to deploy the schema to the current storage using SQL::Translator.
555 Note that this feature is currently EXPERIMENTAL and may not work correctly
556 across all databases, or fully handle complex relationships.
561 my ($self, $sqltargs) = @_;
562 $self->throw_exception("Can't deploy without storage") unless $self->storage;
563 $self->storage->deploy($self, undef, $sqltargs);
570 Matt S. Trout <mst@shadowcatsystems.co.uk>
574 You may distribute this code under the same terms as Perl itself.