NAME¶
DBIx::Class - Extensible and flexible object <-> relational mapper.
WHERE TO START READING¶
See DBIx::Class::Manual::DocMap for an overview of the exhaustive documentation.
To get the most out of DBIx::Class with the least confusion it is strongly
recommended to read (at the very least) the Manuals in the order presented
there.
GETTING HELP/SUPPORT¶
Due to the sheer size of its problem domain, DBIx::Class is a relatively complex
framework. After you start using DBIx::Class questions will inevitably arise.
If you are stuck with a problem or have doubts about a particular approach do
not hesitate to contact us via any of the following options (the list is
sorted by "fastest response time"):
- •
- IRC: irc.perl.org#dbix-class
- •
- Mailing list:
<http://lists.scsys.co.uk/mailman/listinfo/dbix-class>
- •
- RT Bug Tracker:
<https://rt.cpan.org/NoAuth/Bugs.html?Dist=DBIx-Class>
- •
- Twitter: <https://www.twitter.com/dbix_class>
- •
- Web Site: <http://www.dbix-class.org/>
SYNOPSIS¶
For the very impatient: DBIx::Class::Manual::QuickStart
This code in the next step can be generated automatically from an existing
database, see dbicdump from the distribution
"DBIx-Class-Schema-Loader".
Schema classes preparation¶
Create a schema class called
MyApp/Schema.pm:
package MyApp::Schema;
use base qw/DBIx::Class::Schema/;
__PACKAGE__->load_namespaces();
1;
Create a result class to represent artists, who have many CDs, in
MyApp/Schema/Result/Artist.pm:
See DBIx::Class::ResultSource for docs on defining result classes.
package MyApp::Schema::Result::Artist;
use base qw/DBIx::Class::Core/;
__PACKAGE__->table('artist');
__PACKAGE__->add_columns(qw/ artistid name /);
__PACKAGE__->set_primary_key('artistid');
__PACKAGE__->has_many(cds => 'MyApp::Schema::Result::CD', 'artistid');
1;
A result class to represent a CD, which belongs to an artist, in
MyApp/Schema/Result/CD.pm:
package MyApp::Schema::Result::CD;
use base qw/DBIx::Class::Core/;
__PACKAGE__->load_components(qw/InflateColumn::DateTime/);
__PACKAGE__->table('cd');
__PACKAGE__->add_columns(qw/ cdid artistid title year /);
__PACKAGE__->set_primary_key('cdid');
__PACKAGE__->belongs_to(artist => 'MyApp::Schema::Result::Artist', 'artistid');
1;
API usage¶
Then you can use these classes in your application's code:
# Connect to your database.
use MyApp::Schema;
my $schema = MyApp::Schema->connect($dbi_dsn, $user, $pass, \%dbi_params);
# Query for all artists and put them in an array,
# or retrieve them as a result set object.
# $schema->resultset returns a DBIx::Class::ResultSet
my @all_artists = $schema->resultset('Artist')->all;
my $all_artists_rs = $schema->resultset('Artist');
# Output all artists names
# $artist here is a DBIx::Class::Row, which has accessors
# for all its columns. Rows are also subclasses of your Result class.
foreach $artist (@all_artists) {
print $artist->name, "\n";
}
# 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 the next available 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 data
# 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 2nd query
# new() makes a Result object but doesnt insert it into the DB.
# create() is the same as new() then insert().
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
# change the year of all the millennium CDs at once
$millennium_cds_rs->update({ year => 2002 });
DESCRIPTION¶
This is an SQL to OO mapper with an object API inspired by Class::DBI (with 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", "ORDER 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 large new features may be
marked
experimental - such APIs are still usable but may have edge
bugs. Failing test cases are
always welcome and point releases are put
out rapidly as bugs are found and fixed.
We do our best to maintain full backwards compatibility for published APIs,
since DBIx::Class is used in production in many organisations, and even
backwards incompatible changes to non-published APIs will be fixed if they're
reported and doing so doesn't cost the codebase anything.
The test suite is quite substantial, and several developer releases are
generally made to CPAN before the branch for the next release is merged back
to trunk for a major release.
HOW TO CONTRIBUTE¶
Contributions are always welcome, in all usable forms (we especially welcome
documentation improvements). The delivery methods include git- or unified-diff
formatted patches, GitHub pull requests, or plain bug reports either via RT or
the Mailing list. Contributors are generally granted access to the official
repository after their first several patches pass successful review. Don't
hesitate to contact either of the "CAT HERDERS" with any further
questions you may have.
This project is maintained in a git repository. The code and related tools are
accessible at the following locations:
- •
- Official repo:
<git://git.shadowcat.co.uk/dbsrgits/DBIx-Class.git>
- •
- Official gitweb:
<http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=dbsrgits/DBIx-Class.git>
- •
- GitHub mirror: <https://github.com/dbsrgits/DBIx-Class>
- •
- Authorized committers:
<ssh://dbsrgits@git.shadowcat.co.uk/DBIx-Class.git>
- •
- Travis-CI log:
<https://travis-ci.org/dbsrgits/dbix-class/builds>
AUTHORS¶
Even though a large portion of the source
appears to be written by just a
handful of people, this library continues to remain a collaborative effort -
perhaps one of the most successful such projects on CPAN
<
http://cpan.org>. It is important to remember that ideas do not always
result in a direct code contribution, but deserve acknowledgement just the
same. Time and time again the seemingly most insignificant questions and
suggestions have been shown to catalyze monumental improvements in
consistency, accuracy and performance.
The canonical source of authors and their details is the
AUTHORS file at
the root of this distribution (or repository). The canonical source of
per-line authorship is the git repository history itself.
CAT HERDERS¶
The fine folks nudging the project in a particular direction:
ribasushi: Peter Rabbitson
<ribasushi@cpan.org> (present day maintenance and controlled evolution)
castaway: Jess Robinson <castaway@desert-island.me.uk> (lions share
of the reference documentation and manuals)
mst: Matt S Trout <mst@shadowcat.co.uk> (project founder - original
idea, architecture and implementation)
COPYRIGHT AND LICENSE¶
Copyright (c) 2005 by mst, castaway, ribasushi, and other DBIx::Class
"AUTHORS" as listed above and in
AUTHORS.
This library is free software and may be distributed under the same terms as
perl5 itself. See
LICENSE for the complete licensing terms.