DBIx::Class::Schema - composable schemas
package Library::Schema; use base qw/DBIx::Class::Schema/; # 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'); # Elsewhere in your code: my $schema1 = Library::Schema->connect( $dsn, $user, $password, { AutoCommit => 0 }, ); my $schema2 = Library::Schema->connect($coderef_returning_dbh); # fetch objects using Library::Schema::DVD my $resultset = $schema1->resultset('DVD')->search( ... ); my @dvd_objects = $schema2->resultset('DVD')->search( ... );
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.
Registers a class which isa DBIx::Class::ResultSourceProxy. Equivalent to calling:
$schema->register_source($moniker, $component_class->result_source_instance);
Registers the DBIx::Class::ResultSource in the schema with the given moniker.
Retrieves the result class name for the given moniker. For example:
my $class = $schema->class('CD');
my $source = $schema->source('Book');
Returns the DBIx::Class::ResultSource object for the registered moniker.
Returns the source monikers of all source registrations on this schema. For example:
my @source_monikers = $schema->sources;
my $storage = $schema->storage;
Returns the DBIx::Class::Storage object for this Schema.
my $rs = $schema->resultset('DVD');
Returns the DBIx::Class::ResultSet object for the registered moniker.
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.
#
no warnings 'qw';
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 /], });
This is an alternative to "load_classes" above which assumes an alternative layout for automatic class loading. It assumes that all result classes are underneath a sub-namespace of the schema called Result, any corresponding ResultSet classes are underneath a sub-namespace of the schema called ResultSet.
Result
ResultSet
Both of the sub-namespaces are configurable if you don't like the defaults, via the options result_namespace and resultset_namespace.
result_namespace
resultset_namespace
If (and only if) you specify the option default_resultset_class, any found Result classes for which we do not find a corresponding ResultSet class will have their resultset_class set to default_resultset_class.
default_resultset_class
resultset_class
load_namespaces takes care of calling resultset_class for you where neccessary if you didn't do it for yourself.
load_namespaces
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 +.
+
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', );
If you'd like to use multiple namespaces of each type, simply use an arrayref of namespaces for that option. In the case that the same result (or resultset) class exists in multiple namespaces, the latter entries in your 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' ], );
DEPRECATED. You probably wanted compose_namespace.
Actually, you probably just wanted to call connect.
Calls "compose_namespace" in DBIx::Class::Schema to the target namespace, calls "connection" in DBIx::Class::Schema with @db_info on the new schema, then injects the 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 "connect" in DBIx::Class::Schema and use the resulting schema object to operate on DBIx::Class::ResultSet objects with "resultset" in DBIx::Class::Schema for more information.
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 classe from the current schema then the base class.
$additional_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
Sets up a database connection class to inject between the schema and the subclasses that the schema creates.
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". Defaults to ::DBI, which is DBIx::Class::Storage::DBI.
::
DBIx::Class::Storage
::DBI
You want to use this to hardcoded subclasses of DBIx::Class::Storage::DBI in cases where the appropriate subclass is not autodetected, such as when dealing with MSSQL via DBD::Sybase, in which case you'd set it to ::DBI::Sybase::MSSQL.
::DBI::Sybase::MSSQL
Instantiates a new Storage object of type "storage_type" in DBIx::Class::Schema and passes the arguments to $storage->connect_info. Sets the connection in-place on the schema.
See "connect_info" in DBIx::Class::Storage::DBI for DBI-specific syntax, or DBIx::Class::Storage in general.
This is a convenience method. It is equivalent to calling $schema->clone->connection(@info). See "connection" and "clone" for more information.
$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.
@coderef_args
This interface is preferred over using the individual methods "txn_begin", "txn_commit", and "txn_rollback" below.
Begins a transaction (does nothing if AutoCommit is off). Equivalent to calling $schema->storage->txn_begin. See "txn_begin" in DBIx::Class::Storage::DBI for more information.
Commits the current transaction. Equivalent to calling $schema->storage->txn_commit. See "txn_commit" in DBIx::Class::Storage::DBI for more information.
Rolls back the current transaction. Equivalent to calling $schema->storage->txn_rollback. See "txn_rollback" in DBIx::Class::Storage::DBI for more information.
Clones the schema and its associated result_source objects and returns the copy.
Pass this method a resultsource name, and an arrayref of arrayrefs. The arrayrefs should contain a list of column names, followed by one or many sets of matching data for the given columns.
In void context, insert_bulk in DBIx::Class::Storage::DBI is used to insert the data, as this is a fast method. However, insert_bulk currently assumes that your datasets all contain the same type of values, using scalar references in a column in one row, and not in another will probably not work.
insert_bulk
Otherwise, each set of data is inserted into the database using "create" in DBIx::Class::ResultSet, and a arrayref of the resulting row objects is returned.
i.e.,
$schema->populate('Artist', [ [ qw/artistid name/ ], [ 1, 'Popular Band' ], [ 2, 'Indie Band' ], ... ]);
If exception_action is set for this class/object, "throw_exception" will prefer to call this code reference with the exception as an argument, rather than its normal croak or confess action.
exception_action
croak
confess
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 exception_action to suppress a particular exception completely, simply have it return true.
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 });
Whether "throw_exception" should include stack trace information. Defaults to false normally, but defaults to true if $ENV{DBIC_TRACE} is true.
$ENV{DBIC_TRACE}
Throws an exception. Defaults to using Carp::Clan to report errors from 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.
throw_exception
Attempts to deploy the schema to the current storage using SQL::Translator.
Note that this feature is currently EXPERIMENTAL and may not work correctly across all databases, or fully handle complex relationships. Saying that, it has been used successfully by many people, including the core dev team.
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.
$sqlt_args
{ add_drop_table => 1, }
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.
sources
Creates an SQL file based on the Schema, for each of the specified database types, in the given directory. Given a previous version number, this will also create a file containing the ALTER TABLE statements to transform the previous schema into the current one. Note that these statements may contain DROP TABLE or DROP COLUMN statements that can potentially destroy data.
The file names are created using the ddl_filename method below, please override this method in your schema if you would like a different file name format. For the ALTER file, the same format is used, replacing $version in the name with "$preversion-$version".
ddl_filename
If no arguments are passed, then the following default values are used:
Note that this feature is currently EXPERIMENTAL and may not work correctly across all databases, or fully handle complex relationships.
WARNING: Please check all SQL files created, before applying them.
my $filename = $table->ddl_filename($type, $dir, $version, $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.
create_ddl_dir
$dir$schema-$version-$type.sql
You may override this method in your schema if you wish to use a different format.
Matt S. Trout <mst@shadowcatsystems.co.uk>
You may distribute this code under the same terms as Perl itself.
To install DBIx::Class, copy and paste the appropriate command in to your terminal.
cpanm
cpanm DBIx::Class
CPAN shell
perl -MCPAN -e shell install DBIx::Class
For more information on module installation, please visit the detailed CPAN module installation guide.