1DBIx::Class(3) User Contributed Perl Documentation DBIx::Class(3)
2
6 DBIx::Class - Extensible and flexible object <-> relational mapper.
7
9 See DBIx::Class::Manual::DocMap for an overview of the exhaustive
10 documentation. To get the most out of DBIx::Class with the least
11 confusion it is strongly recommended to read (at the very least) the
12 Manuals in the order presented there.
13
15 Due to the sheer size of its problem domain, DBIx::Class is a
16 relatively complex framework. After you start using DBIx::Class
17 questions will inevitably arise. If you are stuck with a problem or
18 have doubts about a particular approach do not hesitate to contact us
19 via any of the following options (the list is sorted by "fastest
20 response time"):
21 · IRC: irc.perl.org#dbix-class
23 · Mailing list:
25 <http://lists.scsys.co.uk/mailman/listinfo/dbix-class>
26 · RT Bug Tracker:
28 <https://rt.cpan.org/NoAuth/Bugs.html?Dist=DBIx-Class>
29 · Twitter: <https://www.twitter.com/dbix_class>
31 · Web Site: <http://www.dbix-class.org/>
33
35 For the very impatient: DBIx::Class::Manual::QuickStart
36 This code in the next step can be generated automatically from an
38 existing database, see dbicdump from the distribution
39 "DBIx-Class-Schema-Loader".
40 Schema classes preparation
42 Create a schema class called MyApp/Schema.pm:
43 package MyApp::Schema;
45 use base qw/DBIx::Class::Schema/;
46 __PACKAGE__->load_namespaces();
48 1;
50 Create a result class to represent artists, who have many CDs, in
52 MyApp/Schema/Result/Artist.pm:
53 See DBIx::Class::ResultSource for docs on defining result classes.
55 package MyApp::Schema::Result::Artist;
57 use base qw/DBIx::Class::Core/;
58 __PACKAGE__->table('artist');
60 __PACKAGE__->add_columns(qw/ artistid name /);
61 __PACKAGE__->set_primary_key('artistid');
62 __PACKAGE__->has_many(cds => 'MyApp::Schema::Result::CD', 'artistid');
63 1;
65 A result class to represent a CD, which belongs to an artist, in
67 MyApp/Schema/Result/CD.pm:
68 package MyApp::Schema::Result::CD;
70 use base qw/DBIx::Class::Core/;
71 __PACKAGE__->load_components(qw/InflateColumn::DateTime/);
73 __PACKAGE__->table('cd');
74 __PACKAGE__->add_columns(qw/ cdid artistid title year /);
75 __PACKAGE__->set_primary_key('cdid');
76 __PACKAGE__->belongs_to(artist => 'MyApp::Schema::Result::Artist', 'artistid');
77 1;
79 API usage
81 Then you can use these classes in your application's code:
82 # Connect to your database.
84 use MyApp::Schema;
85 my $schema = MyApp::Schema->connect($dbi_dsn, $user, $pass, \%dbi_params);
86 # Query for all artists and put them in an array,
88 # or retrieve them as a result set object.
89 # $schema->resultset returns a DBIx::Class::ResultSet
90 my @all_artists = $schema->resultset('Artist')->all;
91 my $all_artists_rs = $schema->resultset('Artist');
92 # Output all artists names
94 # $artist here is a DBIx::Class::Row, which has accessors
95 # for all its columns. Rows are also subclasses of your Result class.
96 foreach $artist (@all_artists) {
97 print $artist->name, "\n";
98 }
99 # Create a result set to search for artists.
101 # This does not query the DB.
102 my $johns_rs = $schema->resultset('Artist')->search(
103 # Build your WHERE using an SQL::Abstract structure:
104 { name => { like => 'John%' } }
105 );
106 # Execute a joined query to get the cds.
108 my @all_john_cds = $johns_rs->search_related('cds')->all;
109 # Fetch the next available row.
111 my $first_john = $johns_rs->next;
112 # Specify ORDER BY on the query.
114 my $first_john_cds_by_title_rs = $first_john->cds(
115 undef,
116 { order_by => 'title' }
117 );
118 # Create a result set that will fetch the artist data
120 # at the same time as it fetches CDs, using only one query.
121 my $millennium_cds_rs = $schema->resultset('CD')->search(
122 { year => 2000 },
123 { prefetch => 'artist' }
124 );
125 my $cd = $millennium_cds_rs->next; # SELECT ... FROM cds JOIN artists ...
127 my $cd_artist_name = $cd->artist->name; # Already has the data so no 2nd query
128 # new() makes a Result object but doesn't insert it into the DB.
130 # create() is the same as new() then insert().
131 my $new_cd = $schema->resultset('CD')->new({ title => 'Spoon' });
132 $new_cd->artist($cd->artist);
133 $new_cd->insert; # Auto-increment primary key filled in after INSERT
134 $new_cd->title('Fork');
135 $schema->txn_do(sub { $new_cd->update }); # Runs the update in a transaction
137 # change the year of all the millennium CDs at once
139 $millennium_cds_rs->update({ year => 2002 });
140
142 This is an SQL to OO mapper with an object API inspired by Class::DBI
143 (with a compatibility layer as a springboard for porting) and a
144 resultset API that allows abstract encapsulation of database
145 operations. It aims to make representing queries in your code as perl-
146 ish as possible while still providing access to as many of the
147 capabilities of the database as possible, including retrieving related
148 records from multiple tables in a single query, "JOIN", "LEFT JOIN",
149 "COUNT", "DISTINCT", "GROUP BY", "ORDER BY" and "HAVING" support.
150 DBIx::Class can handle multi-column primary and foreign keys, complex
152 queries and database-level paging, and does its best to only query the
153 database in order to return something you've directly asked for. If a
154 resultset is used as an iterator it only fetches rows off the statement
155 handle as requested in order to minimise memory usage. It has auto-
156 increment support for SQLite, MySQL, PostgreSQL, Oracle, SQL Server and
157 DB2 and is known to be used in production on at least the first four,
158 and is fork- and thread-safe out of the box (although your DBD may not
159 be).
160 This project is still under rapid development, so large new features
162 may be marked experimental - such APIs are still usable but may have
163 edge bugs. Failing test cases are always welcome and point releases
164 are put out rapidly as bugs are found and fixed.
165 We do our best to maintain full backwards compatibility for published
167 APIs, since DBIx::Class is used in production in many organisations,
168 and even backwards incompatible changes to non-published APIs will be
169 fixed if they're reported and doing so doesn't cost the codebase
170 anything.
171 The test suite is quite substantial, and several developer releases are
173 generally made to CPAN before the branch for the next release is merged
174 back to trunk for a major release.
175
177 Contributions are always welcome, in all usable forms (we especially
178 welcome documentation improvements). The delivery methods include git-
179 or unified-diff formatted patches, GitHub pull requests, or plain bug
180 reports either via RT or the Mailing list. Do not hesitate to get in
181 touch with any further questions you may have.
182 This project is maintained in a git repository. The code and related
184 tools are accessible at the following locations:
185 · Current git repository: <https://github.com/Perl5/DBIx-Class>
187 · Travis-CI log: <https://travis-ci.org/Perl5/DBIx-Class/branches>
189
191 Even though a large portion of the source appears to be written by just
192 a handful of people, this library continues to remain a collaborative
193 effort - perhaps one of the most successful such projects on CPAN
194 <http://cpan.org>. It is important to remember that ideas do not
195 always result in a direct code contribution, but deserve
196 acknowledgement just the same. Time and time again the seemingly most
197 insignificant questions and suggestions have been shown to catalyze
198 monumental improvements in consistency, accuracy and performance.
199 The canonical source of authors and their details is the AUTHORS file
201 at the root of this distribution (or repository). The canonical source
202 of per-line authorship is the git repository history itself.
203
205 Copyright (c) 2005 by mst, castaway, ribasushi, and other DBIx::Class
206 "AUTHORS" as listed above and in AUTHORS.
207 This library is free software and may be distributed under the same
209 terms as perl5 itself. See LICENSE for the complete licensing terms.
210perl v5.30.1 2020-01-29 DBIx::Class(3)