Provided by: libdbix-class-perl_0.08250-2_all bug

NAME

       DBIx::Class::Schema - composable schemas

SYNOPSIS

         package Library::Schema;
         use base qw/DBIx::Class::Schema/;

         # load all Result classes in Library/Schema/Result/
         __PACKAGE__->load_namespaces();

         package Library::Schema::Result::CD;
         use base qw/DBIx::Class::Core/;

         __PACKAGE__->load_components(qw/InflateColumn::DateTime/); # for example
         __PACKAGE__->table('cd');

         # Elsewhere in your code:
         my $schema1 = Library::Schema->connect(
           $dsn,
           $user,
           $password,
           { AutoCommit => 1 },
         );

         my $schema2 = Library::Schema->connect($coderef_returning_dbh);

         # fetch objects using Library::Schema::Result::DVD
         my $resultset = $schema1->resultset('DVD')->search( ... );
         my @dvd_objects = $schema2->resultset('DVD')->search( ... );

DESCRIPTION

       Creates database classes based on a schema. This is the recommended way to use DBIx::Class
       and allows you to use more than one concurrent connection with your classes.

       NB: If you're used to Class::DBI it's worth reading the "SYNOPSIS" carefully, as
       DBIx::Class does things a little differently. Note in particular which module inherits off
       which.

SETUP METHODS

   load_namespaces
       Arguments: %options?

         __PACKAGE__->load_namespaces();

         __PACKAGE__->load_namespaces(
            result_namespace => 'Res',
            resultset_namespace => 'RSet',
            default_resultset_class => '+MyDB::Othernamespace::RSet',
         );

       With no arguments, this method uses Module::Find to load all of the Result and ResultSet
       classes under the namespace of the schema from which it is called.  For example,
       "My::Schema" will by default find and load Result classes named "My::Schema::Result::*"
       and ResultSet classes named "My::Schema::ResultSet::*".

       ResultSet classes are associated with Result class of the same name.  For example,
       "My::Schema::Result::CD" will get the ResultSet class "My::Schema::ResultSet::CD" if it is
       present.

       Both Result and ResultSet namespaces are configurable via the "result_namespace" and
       "resultset_namespace" options.

       Another option, "default_resultset_class" specifies a custom default ResultSet class for
       Result classes with no corresponding ResultSet.

       All of the namespace and classname options are by default relative to the schema
       classname.  To specify a fully-qualified name, prefix it with a literal "+".  For example,
       "+Other::NameSpace::Result".

       Warnings

       You will be warned if ResultSet classes are discovered for which there are no matching
       Result classes like this:

         load_namespaces found ResultSet class $classname with no corresponding Result class

       If a Result class is found to already have a ResultSet class set using "resultset_class"
       to some other class, you will be warned like this:

         We found ResultSet class '$rs_class' for '$result', but it seems
         that you had already set '$result' to use '$rs_set' instead

       Examples

         # load My::Schema::Result::CD, My::Schema::Result::Artist,
         #    My::Schema::ResultSet::CD, etc...
         My::Schema->load_namespaces;

         # Override everything to use ugly names.
         # In this example, if there is a My::Schema::Res::Foo, but no matching
         #   My::Schema::RSets::Foo, then Foo will have its
         #   resultset_class set to My::Schema::RSetBase
         My::Schema->load_namespaces(
           result_namespace => 'Res',
           resultset_namespace => 'RSets',
           default_resultset_class => 'RSetBase',
         );

         # Put things in other namespaces
         My::Schema->load_namespaces(
           result_namespace => '+Some::Place::Results',
           resultset_namespace => '+Another::Place::RSets',
         );

       To search multiple namespaces for either Result or ResultSet classes, use an arrayref of
       namespaces for that option.  In the case that the same result (or resultset) class exists
       in multiple namespaces, later entries in the list of namespaces will override earlier
       ones.

         My::Schema->load_namespaces(
           # My::Schema::Results_C::Foo takes precedence over My::Schema::Results_B::Foo :
           result_namespace => [ 'Results_A', 'Results_B', 'Results_C' ],
           resultset_namespace => [ '+Some::Place::RSets', 'RSets' ],
         );

   load_classes
       Arguments: @classes?, { $namespace => [ @classes ] }+

       "load_classes" is an alternative method to "load_namespaces", both of which serve similar
       purposes, each with different advantages and disadvantages.  In the general case you
       should use "load_namespaces", unless you need to be able to specify that only specific
       classes are loaded at runtime.

       With no arguments, this method uses Module::Find to find all classes under the schema's
       namespace. Otherwise, this method loads the classes you specify (using use), and registers
       them (using "register_class").

       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.

       If any classes found do not appear to be Result class files, you will get the following
       warning:

          Failed to load $comp_class. Can't find source_name method. Is
          $comp_class really a full DBIC result class? Fix it, move it elsewhere,
          or make your load_classes call more specific.

       Example:

         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 /],
         });

   storage_type
       Arguments: $storage_type|{$storage_type, \%args}
       Return Value: $storage_type|{$storage_type, \%args}
       Default value: DBIx::Class::Storage::DBI

       Set the storage class that will be instantiated when "connect" is called.  If the
       classname starts with "::", the prefix "DBIx::Class::Storage" is assumed by "connect".

       You want to use this to set subclasses of DBIx::Class::Storage::DBI in cases where the
       appropriate subclass is not autodetected.

       If your storage type requires instantiation arguments, those are defined as a second
       argument in the form of a hashref and the entire value needs to be wrapped into an
       arrayref or a hashref.  We support both types of refs here in order to play nice with your
       Config::[class] or your choice. See DBIx::Class::Storage::DBI::Replicated for an example
       of this.

   exception_action
       Arguments: $code_reference
       Return Value: $code_reference
       Default value: None

       When "throw_exception" is invoked and "exception_action" is set to a code reference, this
       reference will be called instead of "throw" in DBIx::Class::Exception, with the exception
       message passed as the only argument.

       Your custom throw code must rethrow the exception, as "throw_exception" is an integral
       part of DBIC's internal execution control flow.

       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(@_) });

   stacktrace
       Arguments: boolean

       Whether "throw_exception" should include stack trace information.  Defaults to false
       normally, but defaults to true if $ENV{DBIC_TRACE} is true.

   sqlt_deploy_hook
       Arguments: $sqlt_schema

       An optional sub which you can declare in your own Schema class that will get passed the
       SQL::Translator::Schema object when you deploy the schema via "create_ddl_dir" or
       "deploy".

       For an example of what you can do with this, see "Adding Indexes And Functions To Your
       SQL" in DBIx::Class::Manual::Cookbook.

       Note that sqlt_deploy_hook is called by "deployment_statements", which in turn is called
       before "deploy". Therefore the hook can be used only to manipulate the
       SQL::Translator::Schema object before it is turned into SQL fed to the database. If you
       want to execute post-deploy statements which can not be generated by SQL::Translator, the
       currently suggested method is to overload "deploy" and use dbh_do.

METHODS

   connect
       Arguments: @connectinfo
       Return Value: $new_schema

       Creates and returns a new Schema object. The connection info set on it is used to create a
       new instance of the storage backend and set it on the Schema object.

       See "connect_info" in DBIx::Class::Storage::DBI for DBI-specific syntax on the
       @connectinfo argument, or DBIx::Class::Storage in general.

       Note that "connect_info" expects an arrayref of arguments, but "connect" does not.
       "connect" wraps its arguments in an arrayref before passing them to "connect_info".

       Overloading

       "connect" is a convenience method. It is equivalent to calling
       $schema->clone->connection(@connectinfo). To write your own overloaded version, overload
       "connection" instead.

   resultset
       Arguments: $source_name
       Return Value: $resultset

         my $rs = $schema->resultset('DVD');

       Returns the DBIx::Class::ResultSet object for the registered source name.

   sources
       Return Value: @source_names

         my @source_names = $schema->sources;

       Lists names of all the sources registered on this Schema object.

   source
       Arguments: $source_name
       Return Value: $result_source

         my $source = $schema->source('Book');

       Returns the DBIx::Class::ResultSource object for the registered source name.

   class
       Arguments: $source_name
       Return Value: $classname

         my $class = $schema->class('CD');

       Retrieves the Result class name for the given source name.

   txn_do
       Arguments: $coderef, @coderef_args?
       Return Value: The return value of $coderef

       Executes $coderef with (optional) arguments @coderef_args atomically, returning its result
       (if any). Equivalent to calling $schema->storage->txn_do.  See "txn_do" in
       DBIx::Class::Storage for more information.

       This interface is preferred over using the individual methods "txn_begin", "txn_commit",
       and "txn_rollback" below.

       WARNING: If you are connected with "AutoCommit => 0" the transaction is considered nested,
       and you will still need to call "txn_commit" to write your changes when appropriate. You
       will also want to connect with "auto_savepoint => 1" to get partial rollback to work, if
       the storage driver for your database supports it.

       Connecting with "AutoCommit => 1" is recommended.

   txn_scope_guard
       Runs "txn_scope_guard" on the schema's storage. See "txn_scope_guard" in
       DBIx::Class::Storage.

   txn_begin
       Begins a transaction (does nothing if AutoCommit is off). Equivalent to calling
       $schema->storage->txn_begin. See "txn_begin" in DBIx::Class::Storage for more information.

   txn_commit
       Commits the current transaction. Equivalent to calling $schema->storage->txn_commit. See
       "txn_commit" in DBIx::Class::Storage for more information.

   txn_rollback
       Rolls back the current transaction. Equivalent to calling $schema->storage->txn_rollback.
       See "txn_rollback" in DBIx::Class::Storage for more information.

   storage
         my $storage = $schema->storage;

       Returns the DBIx::Class::Storage object for this Schema. Grab this if you want to turn on
       SQL statement debugging at runtime, or set the quote character. For the default storage,
       the documentation can be found in DBIx::Class::Storage::DBI.

   populate
       Arguments: $source_name, [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
       Return Value: \@result_objects (scalar context) | @result_objects (list context)

       A convenience shortcut to "populate" in DBIx::Class::ResultSet. Equivalent to:

        $schema->resultset($source_name)->populate([...]);

       NOTE
           The context of this method call has an important effect on what is submitted to
           storage. In void context data is fed directly to fastpath insertion routines provided
           by the underlying storage (most often "execute_for_fetch" in DBI), bypassing the new
           and insert calls on the Result class, including any augmentation of these methods
           provided by components. For example if you are using something like
           DBIx::Class::UUIDColumns to create primary keys for you, you will find that your PKs
           are empty.  In this case you will have to explicitly force scalar or list context in
           order to create those values.

   connection
       Arguments: @args
       Return Value: $new_schema

       Similar to "connect" except sets the storage object and connection data in-place on the
       Schema class. You should probably be calling "connect" to get a proper Schema object
       instead.

       Overloading

       Overload "connection" to change the behaviour of "connect".

   compose_namespace
       Arguments: $target_namespace, $additional_base_class?
       Retur Value: $new_schema

       For each 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 DBIx::Class::ResultSource object to the new $schema
       object. If $additional_base_class is given, the new composed classes will inherit from
       first the corresponding class 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

   svp_begin
       Creates a new savepoint (does nothing outside a transaction).  Equivalent to calling
       $schema->storage->svp_begin.  See "svp_begin" in DBIx::Class::Storage for more
       information.

   svp_release
       Releases a savepoint (does nothing outside a transaction).  Equivalent to calling
       $schema->storage->svp_release.  See "svp_release" in DBIx::Class::Storage for more
       information.

   svp_rollback
       Rollback to a savepoint (does nothing outside a transaction).  Equivalent to calling
       $schema->storage->svp_rollback.  See "svp_rollback" in DBIx::Class::Storage for more
       information.

   clone
       Arguments: %attrs?
       Return Value: $new_schema

       Clones the schema and its associated result_source objects and returns the copy. The
       resulting copy will have the same attributes as the source schema, except for those
       attributes explicitly overridden by the provided %attrs.

   throw_exception
       Arguments: $message

       Throws an exception. Obeys the exemption rules of DBIx::Class::Carp to report errors from
       outer-user's perspective. See "exception_action" for details on overriding this method's
       behavior.  If "stacktrace" is turned on, "throw_exception"'s default behavior will provide
       a detailed stack trace.

   deploy
       Arguments: \%sqlt_args, $dir

       Attempts to deploy the schema to the current storage using SQL::Translator.

       See "METHODS" in SQL::Translator for a list of values for "\%sqlt_args".  The most common
       value for this would be "{ add_drop_table => 1 }" to have the SQL produced include a "DROP
       TABLE" statement for each table created. For quoting purposes supply "quote_identifiers".

       Additionally, the DBIx::Class parser accepts a "sources" parameter as a hash ref or an
       array ref, containing a list of source to deploy. If present, then only the sources listed
       will get deployed. Furthermore, you can use the "add_fk_index" parser parameter to prevent
       the parser from creating an index for each FK.

   deployment_statements
       Arguments: See "deployment_statements" in DBIx::Class::Storage::DBI
       Return Value: $listofstatements

       A convenient shortcut to "$self->storage->deployment_statements($self, @args)".  Returns
       the SQL statements used by "deploy" and "deploy" in DBIx::Class::Schema::Storage.

   create_ddl_dir
       Arguments: See "create_ddl_dir" in DBIx::Class::Storage::DBI

       A convenient shortcut to "$self->storage->create_ddl_dir($self, @args)".

       Creates an SQL file based on the Schema, for each of the specified database types, in the
       given directory.

   ddl_filename
       Arguments: $database-type, $version, $directory, $preversion
       Return Value: $normalised_filename

         my $filename = $table->ddl_filename($type, $version, $dir, $preversion)

       This method is called by "create_ddl_dir" to compose a file name out of the supplied
       directory, database type and version number. The default file name format is:
       "$dir$schema-$version-$type.sql".

       You may override this method in your schema if you wish to use a different format.

        WARNING

        Prior to DBIx::Class version 0.08100 this method had a different signature:

           my $filename = $table->ddl_filename($type, $dir, $version, $preversion)

        In recent versions variables $dir and $version were reversed in order to
        bring the signature in line with other Schema/Storage methods. If you
        really need to maintain backward compatibility, you can do the following
        in any overriding methods:

           ($dir, $version) = ($version, $dir) if ($DBIx::Class::VERSION < 0.08100);

   thaw
       Provided as the recommended way of thawing schema objects. You can call "Storable::thaw"
       directly if you wish, but the thawed objects will not have a reference to any schema, so
       are rather useless.

   freeze
       This doesn't actually do anything more than call "nfreeze" in Storable, it is just
       provided here for symmetry.

   dclone
       Arguments: $object
       Return Value: dcloned $object

       Recommended way of dcloning DBIx::Class::Row and DBIx::Class::ResultSet objects so their
       references to the schema object (which itself is not cloned) are properly maintained.

   schema_version
       Returns the current schema class' $VERSION in a normalised way.

   register_class
       Arguments: $source_name, $component_class

       This method is called by "load_namespaces" and "load_classes" to install the found classes
       into your Schema. You should be using those instead of this one.

       You will only need this method if you have your Result classes in files which are not
       named after the packages (or all in the same file). You may also need it to register
       classes at runtime.

       Registers a class which isa DBIx::Class::ResultSourceProxy. Equivalent to calling:

         $schema->register_source($source_name, $component_class->result_source_instance);

   register_source
       Arguments: $source_name, $result_source

       This method is called by "register_class".

       Registers the DBIx::Class::ResultSource in the schema with the given source name.

   unregister_source
       Arguments: $source_name

       Removes the DBIx::Class::ResultSource from the schema for the given source name.

   register_extra_source
       Arguments: $source_name, $result_source

       As "register_source" but should be used if the result class already has a source and you
       want to register an extra one.

   compose_connection (DEPRECATED)
       Arguments: $target_namespace, @db_info
       Return Value: $new_schema

       DEPRECATED. You probably wanted compose_namespace.

       Actually, you probably just wanted to call connect.

AUTHOR AND CONTRIBUTORS

       See AUTHOR and CONTRIBUTORS in DBIx::Class

LICENSE

       You may distribute this code under the same terms as Perl itself.