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DBIx::Class.3pm

NAME

DBIx::Class - Extensible and flexible object <-> relational mapper.

SYNOPSIS

Create a schema class called DB/Main.pm:

   package DB::Main;
   use base qw/DBIx::Class::Schema/;
 
 

   __PACKAGE__->load_classes();
 
 

   1;
 
 

Create a table class to represent artists, who have many CDs, in DB/Main/Artist.pm:

   package DB::Main::Artist;
   use base qw/DBIx::Class/;
 
 

   __PACKAGE__->load_components(qw/PK::Auto Core/);
   __PACKAGE__->table('artist');
   __PACKAGE__->add_columns(qw/ artistid name /);
   __PACKAGE__->set_primary_key('artistid');
   __PACKAGE__->has_many(cds => 'DB::Main::CD');
 
 

   1;
 
 

A table class to represent a CD, which belongs to an artist, in DB/Main/CD.pm:

   package DB::Main::CD;
   use base qw/DBIx::Class/;
 
 

   __PACKAGE__->load_components(qw/PK::Auto Core/);
   __PACKAGE__->table('cd');
   __PACKAGE__->add_columns(qw/ cdid artist title year /);
   __PACKAGE__->set_primary_key('cdid');
   __PACKAGE__->belongs_to(artist => 'DB::Main::Artist');
 
 

   1;
 
 

Then you can use these classes in your application's code:

   # Connect to your database.
   use DB::Main;
   my $schema = DB::Main->connect($dbi_dsn, $user, $pass, \%dbi_params);
 
 

   # Query for all artists and put them in an array,
   # or retrieve them as a result set object.
   my @all_artists = $schema->resultset('Artist')->all;
   my $all_artists_rs = $schema->resultset('Artist');
 
 

   # Create a result set to search for artists.
   # This does not query the DB.
   my $johns_rs = $schema->resultset('Artist')->search(
     # Build your WHERE using an SQL::Abstract structure:
     { name => { like => 'John%' } }
   );
 
 

   # Execute a joined query to get the cds.
   my @all_john_cds = $johns_rs->search_related('cds')->all;
 
 

   # Fetch only the next row.
   my $first_john = $johns_rs->next;
 
 

   # Specify ORDER BY on the query.
   my $first_john_cds_by_title_rs = $first_john->cds(
     undef,
     { order_by => 'title' }
   );
 
 

   # Create a result set that will fetch the artist relationship
   # at the same time as it fetches CDs, using only one query.
   my $millennium_cds_rs = $schema->resultset('CD')->search(
     { year => 2000 },
     { prefetch => 'artist' }
   );
 
 

   my $cd = $millennium_cds_rs->next; # SELECT ... FROM cds JOIN artists ...
   my $cd_artist_name = $cd->artist->name; # Already has the data so no query
 
 

   my $new_cd = $schema->resultset('CD')->new({ title => 'Spoon' });
   $new_cd->artist($cd->artist);
   $new_cd->insert; # Auto-increment primary key filled in after INSERT
   $new_cd->title('Fork');
 
 

   $schema->txn_do(sub { $new_cd->update }); # Runs the update in a transaction
 
 

   $millennium_cds_rs->update({ year => 2002 }); # Single-query bulk update
 
 

DESCRIPTION

This is an SQL to OO mapper with an object API inspired by Class::DBI (and a compatibility layer as a springboard for porting) and a resultset API that allows abstract encapsulation of database operations. It aims to make representing queries in your code as perl-ish as possible while still providing access to as many of the capabilities of the database as possible, including retrieving related records from multiple tables in a single query, JOIN, LEFT JOIN, COUNT, DISTINCT, GROUP BY and HAVING support.

DBIx::Class can handle multi-column primary and foreign keys, complex queries and database-level paging, and does its best to only query the database in order to return something you've directly asked for. If a resultset is used as an iterator it only fetches rows off the statement handle as requested in order to minimise memory usage. It has auto-increment support for SQLite, MySQL, PostgreSQL, Oracle, SQL Server and DB2 and is known to be used in production on at least the first four, and is fork- and thread-safe out of the box (although your DBD may not be).

This project is still under rapid development, so features added in the latest major release may not work 100% yet --- check the Changes if you run into trouble, and beware of anything explicitly marked EXPERIMENTAL. Failing test cases are *always* welcome and point releases are put out rapidly as bugs are found and fixed.

Even so, we do our best to maintain full backwards compatibility for published APIs, since DBIx::Class is used in production in a number of organisations. The test suite is quite substantial, and several developer releases are generally made to CPAN before the -current branch is merged back to trunk for a major release.

The community can be found via:

   Mailing list: http://lists.rawmode.org/mailman/listinfo/dbix-class/
 
 

   SVN: http://dev.catalyst.perl.org/repos/bast/trunk/DBIx-Class/
 
 

   Wiki: http://dbix-class.shadowcatsystems.co.uk/
 
 

   IRC: irc.perl.org#dbix-class
 
 

WHERE TO GO NEXT

DBIx::Class::Manual::DocMap lists each task you might want help on, and the modules where you will find documentation.

AUTHOR

mst: Matt S. Trout <mst@shadowcatsystems.co.uk>

CONTRIBUTORS

abraxxa: Alexander Hartmaier <alex_hartmaier@hotmail.com>

andyg: Andy Grundman <andy@hybridized.org>

ank: Andres Kievsky

ash: Ash Berlin <ash@cpan.org>

blblack: Brandon L. Black <blblack@gmail.com>

bluefeet: Aran Deltac <bluefeet@cpan.org>

captainL: Luke Saunders <luke.saunders@gmail.com>

castaway: Jess Robinson

claco: Christopher H. Laco

clkao: CL Kao

da5id: David Jack Olrik <djo@cpan.org>

dkubb: Dan Kubb <dan.kubb-cpan@onautopilot.com>

dnm: Justin Wheeler <jwheeler@datademons.com>

draven: Marcus Ramberg <mramberg@cpan.org>

dwc: Daniel Westermann-Clark <danieltwc@cpan.org>

dyfrgi: Michael Leuchtenburg <michael@slashhome.org>

gphat: Cory G Watson <gphat@cpan.org>

jesper: Jesper Krogh

jguenther: Justin Guenther <jguenther@cpan.org>

jshirley: J. Shirley <jshirley@gmail.com>

konobi: Scott McWhirter

LTJake: Brian Cassidy <bricas@cpan.org>

ned: Neil de Carteret

nigel: Nigel Metheringham <nigelm@cpan.org>

ningu: David Kamholz <dkamholz@cpan.org>

Numa: Dan Sully <daniel@cpan.org>

paulm: Paul Makepeace

penguin: K J Cheetham

phaylon: Robert Sedlacek <phaylon@dunkelheit.at>

quicksilver: Jules Bean

sc_: Just Another Perl Hacker

scotty: Scotty Allen <scotty@scottyallen.com>

sszabo: Stephan Szabo <sszabo@bigpanda.com>

Todd Lipcon

typester: Daisuke Murase <typester@cpan.org>

victori: Victor Igumnov <victori@cpan.org>

wdh: Will Hawes

willert: Sebastian Willert <willert@cpan.org>

zamolxes: Bogdan Lucaciu <bogdan@wiz.ro>

LICENSE

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