use strict;
use warnings;
-use DBIx::Class::DB;
+
+use Carp::Clan qw/^DBIx::Class/;
+use Scalar::Util qw/weaken/;
use base qw/DBIx::Class/;
-__PACKAGE__->load_components(qw/Exception/);
-__PACKAGE__->mk_classdata('class_registrations' => {});
-__PACKAGE__->mk_classdata('storage_type' => 'DBI');
+__PACKAGE__->mk_classdata('class_mappings' => {});
+__PACKAGE__->mk_classdata('source_registrations' => {});
+__PACKAGE__->mk_classdata('storage_type' => '::DBI');
__PACKAGE__->mk_classdata('storage');
+__PACKAGE__->mk_classdata('exception_action');
=head1 NAME
=head1 SYNOPSIS
-in My/Schema.pm
-
- package My::Schema;
-
+ package Library::Schema;
use base qw/DBIx::Class::Schema/;
- __PACKAGE__->load_classes(qw/Foo Bar Baz/);
-
-in My/Schema/Foo.pm
-
- package My::Schema::Foo;
+ # load Library::Schema::CD, Library::Schema::Book, Library::Schema::DVD
+ __PACKAGE__->load_classes(qw/CD Book DVD/);
+ package Library::Schema::CD;
use base qw/DBIx::Class/;
+ __PACKAGE__->load_components(qw/PK::Auto Core/); # for example
+ __PACKAGE__->table('cd');
- __PACKAGE__->load_components(qw/PK::Auto::Pg Core/); # for example
- __PACKAGE__->table('foo');
- ...
-
-in My/DB.pm
-
- use My::Schema;
-
- My::Schema->compose_connection('My::DB', $dsn, $user, $pass, $attrs);
+ # Elsewhere in your code:
+ my $schema1 = Library::Schema->connect(
+ $dsn,
+ $user,
+ $password,
+ { AutoCommit => 0 },
+ );
-then in app code
+ my $schema2 = Library::Schema->connect($coderef_returning_dbh);
- my @obj = My::DB::Foo->search({}); # My::DB::Foo isa My::Schema::Foo My::DB
+ # fetch objects using Library::Schema::DVD
+ my $resultset = $schema1->resultset('DVD')->search( ... );
+ my @dvd_objects = $schema2->resultset('DVD')->search( ... );
=head1 DESCRIPTION
-Creates database classes based on a schema. This allows you to have more than
-one concurrent connection using the same database classes, by making
-subclasses under a new namespace for each connection. If you only need one
-class, you should probably use L<DBIx::Class::DB> directly instead.
+Creates database classes based on a schema. This is the recommended way to
+use L<DBIx::Class> and allows you to use more than one concurrent connection
+with your classes.
NB: If you're used to L<Class::DBI> it's worth reading the L</SYNOPSIS>
-carefully as DBIx::Class does things a little differently. Note in
+carefully, as DBIx::Class does things a little differently. Note in
particular which module inherits off which.
=head1 METHODS
-=head2 register_class <component> <component_class>
+=head2 register_class
-Registers the class in the schema's class_registrations. This is a hash
-containing database classes, keyed by their monikers. It's used by
-compose_connection to create/modify all the existing database classes.
+=over 4
+
+=item Arguments: $moniker, $component_class
+
+=back
+
+Registers a class which isa DBIx::Class::ResultSourceProxy. Equivalent to
+calling:
+
+ $schema->register_source($moniker, $component_class->result_source_instance);
=cut
sub register_class {
- my ($class, $name, $to_register) = @_;
- my %reg = %{$class->class_registrations};
- $reg{$name} = $to_register;
- $class->class_registrations(\%reg);
+ my ($self, $moniker, $to_register) = @_;
+ $self->register_source($moniker => $to_register->result_source_instance);
}
-=head2 registered_classes
+=head2 register_source
-Simple read-only accessor for the schema's registered classes. See
-register_class above if you want to modify it.
+=over 4
+=item Arguments: $moniker, $result_source
+
+=back
+
+Registers the L<DBIx::Class::ResultSource> in the schema with the given
+moniker.
=cut
-sub registered_classes {
- return values %{shift->class_registrations};
+sub register_source {
+ my ($self, $moniker, $source) = @_;
+ my %reg = %{$self->source_registrations};
+ $reg{$moniker} = $source;
+ $self->source_registrations(\%reg);
+ $source->schema($self);
+ weaken($source->{schema}) if ref($self);
+ if ($source->result_class) {
+ my %map = %{$self->class_mappings};
+ $map{$source->result_class} = $moniker;
+ $self->class_mappings(\%map);
+ }
}
=head2 class
- my $class = $schema->class('Foo');
+=over 4
+
+=item Arguments: $moniker
-Shortcut to retrieve a single class by its registered name
+=item Return Value: $classname
+
+=back
+
+Retrieves the result class name for the given moniker. For example:
+
+ my $class = $schema->class('CD');
=cut
sub class {
- my ($self, $class) = @_;
- return $self->class_registrations->{$class};
+ my ($self, $moniker) = @_;
+ return $self->source($moniker)->result_class;
}
=head2 source
- my $source = $schema->source('Foo');
+=over 4
+
+=item Arguments: $moniker
-Returns the result source object for the registered name
+=item Return Value: $result_source
+
+=back
+
+ my $source = $schema->source('Book');
+
+Returns the L<DBIx::Class::ResultSource> object for the registered moniker.
=cut
sub source {
- my ($self, $class) = @_;
- return $self->class_registrations->{$class}->result_source;
+ my ($self, $moniker) = @_;
+ my $sreg = $self->source_registrations;
+ return $sreg->{$moniker} if exists $sreg->{$moniker};
+
+ # if we got here, they probably passed a full class name
+ my $mapped = $self->class_mappings->{$moniker};
+ $self->throw_exception("Can't find source for ${moniker}")
+ unless $mapped && exists $sreg->{$mapped};
+ return $sreg->{$mapped};
}
+=head2 sources
+
+=over 4
+
+=item Return Value: @source_monikers
+
+=back
+
+Returns the source monikers of all source registrations on this schema.
+For example:
+
+ my @source_monikers = $schema->sources;
+
+=cut
+
+sub sources { return keys %{shift->source_registrations}; }
+
=head2 resultset
- my $rs = $schema->resultset('Foo');
+=over 4
-Returns the resultset for the registered name
+=item Arguments: $moniker
+
+=item Return Value: $result_set
+
+=back
+
+ my $rs = $schema->resultset('DVD');
+
+Returns the L<DBIx::Class::ResultSet> object for the registered moniker.
=cut
sub resultset {
- my ($self, $class) = @_;
- return $self->class_registrations->{$class}->result_source->resultset;
+ my ($self, $moniker) = @_;
+ return $self->source($moniker)->resultset;
}
+=head2 load_classes
+
+=over 4
+
+=item Arguments: @classes?, { $namespace => [ @classes ] }+
+
+=back
+
+With no arguments, this method uses L<Module::Find> to find all classes under
+the schema's namespace. Otherwise, this method loads the classes you specify
+(using L<use>), and registers them (using L</"register_class">).
-=head2 load_classes [<classes>, (<class>, <class>), {<namespace> => [<classes>]}]
+It is possible to comment out classes with a leading C<#>, but note that perl
+will think it's a mistake (trying to use a comment in a qw list), so you'll
+need to add C<no warnings 'qw';> before your load_classes call.
-Uses L<Module::Find> to find all classes under the database class' namespace,
-or uses the classes you select. Then it loads the component (using L<use>),
-and registers them (using B<register_class>);
+Example:
-It is possible to comment out classes with a leading '#', but note that perl
-will think it's a mistake (trying to use a comment in a qw list) so you'll
-need to add "no warnings 'qw';" before your load_classes call.
+ My::Schema->load_classes(); # loads My::Schema::CD, My::Schema::Artist,
+ # etc. (anything under the My::Schema namespace)
+
+ # loads My::Schema::CD, My::Schema::Artist, Other::Namespace::Producer but
+ # not Other::Namespace::LinerNotes nor My::Schema::Track
+ My::Schema->load_classes(qw/ CD Artist #Track /, {
+ Other::Namespace => [qw/ Producer #LinerNotes /],
+ });
=cut
sub load_classes {
my ($class, @params) = @_;
-
+
my %comps_for;
-
+
if (@params) {
foreach my $param (@params) {
if (ref $param eq 'ARRAY') {
# filter out commented entries
my @modules = grep { $_ !~ /^#/ } @$param;
-
+
push (@{$comps_for{$class}}, @modules);
}
elsif (ref $param eq 'HASH') {
}
} else {
eval "require Module::Find;";
- $class->throw("No arguments to load_classes and couldn't load".
- " Module::Find ($@)") if $@;
- my @comp = map { substr $_, length "${class}::" } Module::Find::findallmod($class);
+ $class->throw_exception(
+ "No arguments to load_classes and couldn't load Module::Find ($@)"
+ ) if $@;
+ my @comp = map { substr $_, length "${class}::" }
+ Module::Find::findallmod($class);
$comps_for{$class} = \@comp;
}
- foreach my $prefix (keys %comps_for) {
- foreach my $comp (@{$comps_for{$prefix}||[]}) {
- my $comp_class = "${prefix}::${comp}";
- eval "use $comp_class"; # If it fails, assume the user fixed it
- if ($@) {
- die $@ unless $@ =~ /Can't locate/;
+ my @to_register;
+ {
+ no warnings qw/redefine/;
+ local *Class::C3::reinitialize = sub { };
+ foreach my $prefix (keys %comps_for) {
+ foreach my $comp (@{$comps_for{$prefix}||[]}) {
+ my $comp_class = "${prefix}::${comp}";
+ $class->ensure_class_loaded($comp_class);
+ $comp_class->source_name($comp) unless $comp_class->source_name;
+
+ push(@to_register, [ $comp_class->source_name, $comp_class ]);
}
- $class->register_class($comp => $comp_class);
}
}
+ Class::C3->reinitialize;
+
+ foreach my $to (@to_register) {
+ $class->register_class(@$to);
+ # if $class->can('result_source_instance');
+ }
}
-=head2 compose_connection <target> <@db_info>
+=head2 load_namespaces
+
+=over 4
-This is the most important method in this class. it takes a target namespace,
-as well as dbh connection info, and creates a L<DBIx::Class::DB> class as
-well as subclasses for each of your database classes in this namespace, using
-this connection.
+=item Arguments: %options?
-It will also setup a ->class method on the target class, which lets you
-resolve database classes based on the schema component name, for example
+=back
- MyApp::DB->class('Foo') # returns MyApp::DB::Foo,
- # which ISA MyApp::Schema::Foo
+This is an alternative to L</load_classes> above which assumes an alternative
+layout for automatic class loading. It assumes that all ResultSource classes
+to be loaded are underneath a sub-namespace of the schema called
+"ResultSource", any corresponding ResultSet classes to be underneath a
+sub-namespace of the schema called "ResultSet", and any corresponing
+Result classes to be underneath a sub-namespace of the schema called "Result".
-This is the recommended API for accessing Schema generated classes, and
-using it might give you instant advantages with future versions of DBIC.
+All of those sub-namespaces are configurable if you don't like the defaults,
+via the options C<resultsource_namespace>, C<resultset_namespace>, and
+C<result_namespace>, respectively.
+
+If (and only if) you specify the option C<default_resultset_base>, any found
+ResultSource classes that have no manually-created corresponding ResultSet
+class will have one created for them in memory in the C<resultset_namespace>,
+based on C<default_resultset_base>.
+
+All of the namespace and classname options to this method are relative to
+the schema classname by default. To specify a fully-qualified name, prefix
+it with a literal C<+>.
+
+This method requires L<Module::Find> to be installed on the system.
+
+Example:
+
+ # load My::Schema::ResultSource::CD, My::Schema::ResultSource::Artist,
+ # My::Schema::ResultSet::CD, etc...
+ My::Schema->load_namespaces;
+
+ # Override everything...
+ My::Schema->load_namespaces(
+ resultsource_namespace => 'RSources',
+ resultset_namespace => 'RSets',
+ result_namespace => 'Results',
+ default_resultset_base => 'RSetBase',
+ );
+ # ... and if there is a My::Schema::RSources::Foo, but no matching
+ # My::Schema::RSets::Foo, then My::Schema::RSets::Foo will be created
+ # for you in memory, based on My::Schema::RSetBase
+
+ # Put things in other namespaces
+ My::Schema->load_namespaces(
+ resultsource_namespace => '+Some::Place::RSources',
+ resultset_namespace => '+Another::Place::RSets',
+ result_namespace => '+Crazy::Stuff::Results',
+ default_resultset_base => '+You::Never::Know::RSetBase',
+ );
-WARNING: Loading components into Schema classes after compose_connection
-may not cause them to be seen by the classes in your target namespace due
-to the dispatch table approach used by Class::C3. If you do this you may find
-you need to call Class::C3->reinitialize() afterwards to get the behaviour
-you expect.
+
+=cut
+
+sub load_namespaces {
+ my ($class, %args) = @_;
+
+ my $resultsource_namespace = $args{resultsource_namespace} || 'ResultSource';
+ my $resultset_namespace = $args{resultset_namespace} || 'ResultSet';
+ my $result_namespace = $args{result_namespace} || 'Result';
+ my $default_resultset_base = $args{default_resultset_base};
+
+ foreach ($resultsource_namespace, $resultset_namespace,
+ $result_namespace, $default_resultset_base) {
+ next if !$_;
+ $_ = $class . '::' . $_ if !s/^\+//;
+ }
+
+ eval "require Module::Find";
+ $class->throw_exception("Couldn't load Module::Find ($@)") if $@;
+
+ my %sources = map { (substr($_, length "${resultsource_namespace}::"), $_) }
+ Module::Find::findallmod($resultsource_namespace);
+
+ my %resultsets = map { (substr($_, length "${resultset_namespace}::"), $_) }
+ Module::Find::findallmod($resultset_namespace);
+
+ my %results = map { (substr($_, length "${result_namespace}::"), $_) }
+ Module::Find::findallmod($result_namespace);
+
+ my @to_register;
+ {
+ no warnings qw/redefine/;
+ local *Class::C3::reinitialize = sub { };
+ use warnings qw/redefine/;
+
+ foreach my $source (keys %sources) {
+ my $source_class = $sources{$source};
+ $class->ensure_class_loaded($source_class);
+ $source_class->source_name($source) unless $source_class->source_name;
+
+ my $rs_class = delete $resultsets{$source};
+ my $rs_set = $source_class->resultset_class;
+ if(!$rs_set || $rs_set eq 'DBIx::Class::ResultSet') {
+ if($rs_class) {
+ $class->ensure_class_loaded($rs_class);
+ $source_class->resultset_class($rs_class);
+ }
+ elsif($default_resultset_base) {
+ $class->ensure_class_loaded($default_resultset_base);
+ $rs_class = "$resultset_namespace\::$source";
+ { no strict qw/refs/; @{"$rs_class\::ISA"} = ($default_resultset_base); }
+ $source_class->resultset_class($rs_class);
+ }
+ }
+ elsif($rs_set && $rs_class) {
+ warn "We found ResultSet class '$rs_class' for '$source', but it seems "
+ . "that you had already set '$source' to use '$rs_set' instead";
+ }
+
+ push(@to_register, [ $source_class->source_name, $source_class ]);
+ }
+ }
+
+ foreach (sort keys %resultsets) {
+ warn "load_namespaces found ResultSet class $_ with no "
+ . 'corresponding ResultSource';
+ }
+
+ Class::C3->reinitialize;
+ $class->register_class(@$_) for (@to_register);
+
+ foreach my $source (keys %sources) {
+ my $r_class = delete $results{$source};
+ if($r_class) {
+ my $r_set = $class->source($source)->result_class;
+ if(!$r_set || $r_set eq $sources{$source}) {
+ $class->ensure_class_loaded($r_class);
+ $class->source($source)->result_class($r_class);
+ }
+ else {
+ warn "We found Result class '$r_class' for '$source', but it seems "
+ . "that you had already set '$source' to use '$r_set' instead";
+ }
+ }
+ }
+
+ foreach (sort keys %results) {
+ warn "load_namespaces found Result class $_ with no "
+ . 'corresponding ResultSource';
+ }
+
+ return;
+}
+
+=head2 compose_connection
+
+=over 4
+
+=item Arguments: $target_namespace, @db_info
+
+=item Return Value: $new_schema
+
+=back
+
+Calls L<DBIx::Class::Schema/"compose_namespace"> to the target namespace,
+calls L<DBIx::Class::Schema/connection> with @db_info on the new schema,
+then injects the L<DBix::Class::ResultSetProxy> component and a
+resultset_instance classdata entry on all the new classes, in order to support
+$target_namespaces::$class->search(...) method calls.
+
+This is primarily useful when you have a specific need for class method access
+to a connection. In normal usage it is preferred to call
+L<DBIx::Class::Schema/connect> and use the resulting schema object to operate
+on L<DBIx::Class::ResultSet> objects with L<DBIx::Class::Schema/resultset> for
+more information.
=cut
sub compose_connection {
my ($self, $target, @info) = @_;
- my $conn_class = "${target}::_db";
- $self->setup_connection_class($conn_class, @info);
- my $schema = $self->compose_namespace($target, $conn_class);
- $schema->storage($conn_class->storage);
- foreach my $class ($schema->registered_classes) {
- my $source = $class->result_source;
- $source = $source->new($source);
- $source->schema($schema);
- $source->result_class($class);
- $class->mk_classdata(result_source => $source);
+ my $base = 'DBIx::Class::ResultSetProxy';
+ eval "require ${base};";
+ $self->throw_exception
+ ("No arguments to load_classes and couldn't load ${base} ($@)")
+ if $@;
+
+ if ($self eq $target) {
+ # Pathological case, largely caused by the docs on early C::M::DBIC::Plain
+ foreach my $moniker ($self->sources) {
+ my $source = $self->source($moniker);
+ my $class = $source->result_class;
+ $self->inject_base($class, $base);
+ $class->mk_classdata(resultset_instance => $source->resultset);
+ $class->mk_classdata(class_resolver => $self);
+ }
+ $self->connection(@info);
+ return $self;
+ }
+
+ my $schema = $self->compose_namespace($target, $base);
+ {
+ no strict 'refs';
+ *{"${target}::schema"} = sub { $schema };
+ }
+
+ $schema->connection(@info);
+ foreach my $moniker ($schema->sources) {
+ my $source = $schema->source($moniker);
+ my $class = $source->result_class;
+ #warn "$moniker $class $source ".$source->storage;
+ $class->mk_classdata(result_source_instance => $source);
$class->mk_classdata(resultset_instance => $source->resultset);
+ $class->mk_classdata(class_resolver => $schema);
}
return $schema;
}
+=head2 compose_namespace
+
+=over 4
+
+=item Arguments: $target_namespace, $additional_base_class?
+
+=item Return Value: $new_schema
+
+=back
+
+For each L<DBIx::Class::ResultSource> in the schema, this method creates a
+class in the target namespace (e.g. $target_namespace::CD,
+$target_namespace::Artist) that inherits from the corresponding classes
+attached to the current schema.
+
+It also attaches a corresponding L<DBIx::Class::ResultSource> object to the
+new $schema object. If C<$additional_base_class> is given, the new composed
+classes will inherit from first the corresponding classe from the current
+schema then the base class.
+
+For example, for a schema with My::Schema::CD and My::Schema::Artist classes,
+
+ $schema->compose_namespace('My::DB', 'Base::Class');
+ print join (', ', @My::DB::CD::ISA) . "\n";
+ print join (', ', @My::DB::Artist::ISA) ."\n";
+
+will produce the output
+
+ My::Schema::CD, Base::Class
+ My::Schema::Artist, Base::Class
+
+=cut
+
sub compose_namespace {
- my ($class, $target, $base) = @_;
- my %reg = %{ $class->class_registrations };
+ my ($self, $target, $base) = @_;
+ my %reg = %{ $self->source_registrations };
my %target;
my %map;
- my $schema = bless({ }, $class);
- while (my ($comp, $comp_class) = each %reg) {
- my $target_class = "${target}::${comp}";
- $class->inject_base($target_class, $comp_class, ($base ? $base : ()));
- @map{$comp, $comp_class} = ($target_class, $target_class);
+ my $schema = $self->clone;
+ {
+ no warnings qw/redefine/;
+ local *Class::C3::reinitialize = sub { };
+ foreach my $moniker ($schema->sources) {
+ my $source = $schema->source($moniker);
+ my $target_class = "${target}::${moniker}";
+ $self->inject_base(
+ $target_class => $source->result_class, ($base ? $base : ())
+ );
+ $source->result_class($target_class);
+ $target_class->result_source_instance($source)
+ if $target_class->can('result_source_instance');
+ }
}
- $schema->class_registrations(\%map);
+ Class::C3->reinitialize();
{
no strict 'refs';
- *{"${target}::schema"} =
- sub { $schema };
- *{"${target}::class"} =
- sub { shift->schema->class(@_) };
+ foreach my $meth (qw/class source resultset/) {
+ *{"${target}::${meth}"} =
+ sub { shift->schema->$meth(@_) };
+ }
}
- $base->class_resolver($target);
return $schema;
}
-=head2 setup_connection_class <$target> <@info>
+=head2 setup_connection_class
+
+=over 4
-Sets up a database connection class to inject between the schema
-and the subclasses the schema creates.
+=item Arguments: $target, @info
+
+=back
+
+Sets up a database connection class to inject between the schema and the
+subclasses that the schema creates.
=cut
$target->connection(@info);
}
+=head2 connection
+
+=over 4
+
+=item Arguments: @args
+
+=item Return Value: $new_schema
+
+=back
+
+Instantiates a new Storage object of type
+L<DBIx::Class::Schema/"storage_type"> and passes the arguments to
+$storage->connect_info. Sets the connection in-place on the schema. See
+L<DBIx::Class::Storage::DBI/"connect_info"> for more information.
+
+=cut
+
+sub connection {
+ my ($self, @info) = @_;
+ return $self if !@info && $self->storage;
+ my $storage_class = $self->storage_type;
+ $storage_class = 'DBIx::Class::Storage'.$storage_class
+ if $storage_class =~ m/^::/;
+ eval "require ${storage_class};";
+ $self->throw_exception(
+ "No arguments to load_classes and couldn't load ${storage_class} ($@)"
+ ) if $@;
+ my $storage = $storage_class->new($self);
+ $storage->connect_info(\@info);
+ $self->storage($storage);
+ return $self;
+}
+
+=head2 connect
+
+=over 4
+
+=item Arguments: @info
+
+=item Return Value: $new_schema
+
+=back
+
+This is a convenience method. It is equivalent to calling
+$schema->clone->connection(@info). See L</connection> and L</clone> for more
+information.
+
+=cut
+
+sub connect { shift->clone->connection(@_) }
+
+=head2 txn_begin
+
+Begins a transaction (does nothing if AutoCommit is off). Equivalent to
+calling $schema->storage->txn_begin. See
+L<DBIx::Class::Storage::DBI/"txn_begin"> for more information.
+
+=cut
+
+sub txn_begin { shift->storage->txn_begin }
+
+=head2 txn_commit
+
+Commits the current transaction. Equivalent to calling
+$schema->storage->txn_commit. See L<DBIx::Class::Storage::DBI/"txn_commit">
+for more information.
+
+=cut
+
+sub txn_commit { shift->storage->txn_commit }
+
+=head2 txn_rollback
+
+Rolls back the current transaction. Equivalent to calling
+$schema->storage->txn_rollback. See
+L<DBIx::Class::Storage::DBI/"txn_rollback"> for more information.
+
+=cut
+
+sub txn_rollback { shift->storage->txn_rollback }
+
+=head2 txn_do
+
+=over 4
+
+=item Arguments: C<$coderef>, @coderef_args?
+
+=item Return Value: The return value of $coderef
+
+=back
+
+Executes C<$coderef> with (optional) arguments C<@coderef_args> atomically,
+returning its result (if any). If an exception is caught, a rollback is issued
+and the exception is rethrown. If the rollback fails, (i.e. throws an
+exception) an exception is thrown that includes a "Rollback failed" message.
+
+For example,
+
+ my $author_rs = $schema->resultset('Author')->find(1);
+ my @titles = qw/Night Day It/;
+
+ my $coderef = sub {
+ # If any one of these fails, the entire transaction fails
+ $author_rs->create_related('books', {
+ title => $_
+ }) foreach (@titles);
+
+ return $author->books;
+ };
+
+ my $rs;
+ eval {
+ $rs = $schema->txn_do($coderef);
+ };
+
+ if ($@) { # Transaction failed
+ die "something terrible has happened!" #
+ if ($@ =~ /Rollback failed/); # Rollback failed
+
+ deal_with_failed_transaction();
+ }
+
+In a nested transaction (calling txn_do() from within a txn_do() coderef) only
+the outermost transaction will issue a L<DBIx::Class::Schema/"txn_commit"> on
+the Schema's storage, and txn_do() can be called in void, scalar and list
+context and it will behave as expected.
+
+=cut
+
+sub txn_do {
+ my ($self, $coderef, @args) = @_;
+
+ $self->storage or $self->throw_exception
+ ('txn_do called on $schema without storage');
+ ref $coderef eq 'CODE' or $self->throw_exception
+ ('$coderef must be a CODE reference');
+
+ my (@return_values, $return_value);
+
+ $self->txn_begin; # If this throws an exception, no rollback is needed
+
+ my $wantarray = wantarray; # Need to save this since the context
+ # inside the eval{} block is independent
+ # of the context that called txn_do()
+ eval {
+
+ # Need to differentiate between scalar/list context to allow for
+ # returning a list in scalar context to get the size of the list
+ if ($wantarray) {
+ # list context
+ @return_values = $coderef->(@args);
+ } elsif (defined $wantarray) {
+ # scalar context
+ $return_value = $coderef->(@args);
+ } else {
+ # void context
+ $coderef->(@args);
+ }
+ $self->txn_commit;
+ };
+
+ if ($@) {
+ my $error = $@;
+
+ eval {
+ $self->txn_rollback;
+ };
+
+ if ($@) {
+ my $rollback_error = $@;
+ my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION";
+ $self->throw_exception($error) # propagate nested rollback
+ if $rollback_error =~ /$exception_class/;
+
+ $self->throw_exception(
+ "Transaction aborted: $error. Rollback failed: ${rollback_error}"
+ );
+ } else {
+ $self->throw_exception($error); # txn failed but rollback succeeded
+ }
+ }
+
+ return $wantarray ? @return_values : $return_value;
+}
+
+=head2 clone
+
+=over 4
+
+=item Return Value: $new_schema
+
+=back
+
+Clones the schema and its associated result_source objects and returns the
+copy.
+
+=cut
+
+sub clone {
+ my ($self) = @_;
+ my $clone = bless({ (ref $self ? %$self : ()) }, ref $self || $self);
+ foreach my $moniker ($self->sources) {
+ my $source = $self->source($moniker);
+ my $new = $source->new($source);
+ $clone->register_source($moniker => $new);
+ }
+ $clone->storage->set_schema($clone) if $clone->storage;
+ return $clone;
+}
+
+=head2 populate
+
+=over 4
+
+=item Arguments: $moniker, \@data;
+
+=back
+
+Populates the source registered with the given moniker with the supplied data.
+@data should be a list of listrefs -- the first containing column names, the
+second matching values.
+
+i.e.,
+
+ $schema->populate('Artist', [
+ [ qw/artistid name/ ],
+ [ 1, 'Popular Band' ],
+ [ 2, 'Indie Band' ],
+ ...
+ ]);
+
+=cut
+
+sub populate {
+ my ($self, $name, $data) = @_;
+ my $rs = $self->resultset($name);
+ my @names = @{shift(@$data)};
+ my @created;
+ foreach my $item (@$data) {
+ my %create;
+ @create{@names} = @$item;
+ push(@created, $rs->create(\%create));
+ }
+ return @created;
+}
+
+=head2 exception_action
+
+=over 4
+
+=item Arguments: $code_reference
+
+=back
+
+If C<exception_action> is set for this class/object, L</throw_exception>
+will prefer to call this code reference with the exception as an argument,
+rather than its normal <croak> action.
+
+Your subroutine should probably just wrap the error in the exception
+object/class of your choosing and rethrow. If, against all sage advice,
+you'd like your C<exception_action> to suppress a particular exception
+completely, simply have it return true.
+
+Example:
+
+ package My::Schema;
+ use base qw/DBIx::Class::Schema/;
+ use My::ExceptionClass;
+ __PACKAGE__->exception_action(sub { My::ExceptionClass->throw(@_) });
+ __PACKAGE__->load_classes;
+
+ # or:
+ my $schema_obj = My::Schema->connect( .... );
+ $schema_obj->exception_action(sub { My::ExceptionClass->throw(@_) });
+
+ # suppress all exceptions, like a moron:
+ $schema_obj->exception_action(sub { 1 });
+
+=head2 throw_exception
+
+=over 4
+
+=item Arguments: $message
+
+=back
+
+Throws an exception. Defaults to using L<Carp::Clan> to report errors from
+user's perspective. See L</exception_action> for details on overriding
+this method's behavior.
+
+=cut
+
+sub throw_exception {
+ my $self = shift;
+ croak @_ if !$self->exception_action || !$self->exception_action->(@_);
+}
+
+=head2 deploy (EXPERIMENTAL)
+
+=over 4
+
+=item Arguments: $sqlt_args
+
+=back
+
+Attempts to deploy the schema to the current storage using L<SQL::Translator>.
+
+Note that this feature is currently EXPERIMENTAL and may not work correctly
+across all databases, or fully handle complex relationships.
+
+See L<SQL::Translator/METHODS> for a list of values for C<$sqlt_args>. The most
+common value for this would be C<< { add_drop_table => 1, } >> to have the SQL
+produced include a DROP TABLE statement for each table created.
+
+=cut
+
+sub deploy {
+ my ($self, $sqltargs) = @_;
+ $self->throw_exception("Can't deploy without storage") unless $self->storage;
+ $self->storage->deploy($self, undef, $sqltargs);
+}
+
+=head2 create_ddl_dir (EXPERIMENTAL)
+
+=over 4
+
+=item Arguments: \@databases, $version, $directory, $sqlt_args
+
+=back
+
+Creates an SQL file based on the Schema, for each of the specified
+database types, in the given directory.
+
+Note that this feature is currently EXPERIMENTAL and may not work correctly
+across all databases, or fully handle complex relationships.
+
+=cut
+
+sub create_ddl_dir
+{
+ my $self = shift;
+
+ $self->throw_exception("Can't create_ddl_dir without storage") unless $self->storage;
+ $self->storage->create_ddl_dir($self, @_);
+}
+
+=head2 ddl_filename (EXPERIMENTAL)
+
+ my $filename = $table->ddl_filename($type, $dir, $version)
+
+Creates a filename for a SQL file based on the table class name. Not
+intended for direct end user use.
+
+=cut
+
+sub ddl_filename
+{
+ my ($self, $type, $dir, $version) = @_;
+
+ my $filename = ref($self);
+ $filename =~ s/::/-/;
+ $filename = "$dir$filename-$version-$type.sql";
+
+ return $filename;
+}
+
1;
=head1 AUTHORS