3 DBIx::Class::Manual::Intro - Introduction to DBIx::Class
7 So, you are bored with SQL, and want a native Perl interface for your
8 database? Or you've been doing this for a while with L<Class::DBI>,
9 and think there's a better way? You've come to the right place.
10 Let's look at how you can set and use your first native L<DBIx::Class>
13 First we'll see how you can set up your classes yourself. If you want
14 them to be auto-discovered, just skip to the next section, which shows
15 you how to use L<DBIx::Class::Loader>.
17 =head2 Setting it up manually
19 First, you'll need a base class. It should inherit from
20 L<DBIx::Class> like this:
23 use base qw/DBIx::Class/;
25 You will also want to load some of the L<DBIx::Class> components.
26 L<DBIx::Class::Core> provides a good starter set. In addition you'll
27 have to use either L<DBIx::Class::Schema> or L<DBIx::Class::DB>.
28 We'll use C<DB> in this introduction, since it involves less magic.
29 C<Schema> is mostly useful if you want to use multiple database
32 __PACKAGE__->load_components(qw/Core DB/);
34 If you want serial/auto-incrementing primary keys, you should use the
35 L<DBIx::Class::PK::Auto> component for your database. For example, if
36 you're using SQLite add C<PK::Auto::SQLite> to the list:
38 __PACKAGE__->load_components(qw/PK::Auto::SQLite Core DB/);
40 C<PK::Auto> classes exist for many databases; see
41 L<DBIx::Class::PK::Auto> for more information.
43 Once you've loaded the components, it's time to set up your
46 __PACKAGE__->connection('dbi:SQLite:/home/me/myapp/my.db');
48 This method is similar to the normal L<DBI> C<connect> method, and can
49 take username, password, and L<DBI> attribute hash as well as the DSN.
51 With that out of the way, we can define our first table class:
53 package MyApp::DB::Album;
54 use base qw/MyApp::DB/;
56 Then we specify which table it uses,
58 __PACKAGE__->table('album');
60 and specify which columns it has.
62 __PACKAGE__->add_columns(qw/albumid artist title label year/);
64 This will automatically create accessors for each of the columns, so
65 that you can read/update the values in rows you've retrieved.
67 Also, you need to tell it which column is the primary key:
69 __PACKAGE__->set_primary_key('albumid');
71 If you have a primary key composed of multiple columns, just pass a
74 That's pretty much all you need for a basic setup. If you have more
75 advanced needs like using more than one database connection for the
76 same class, see L<DBIx::Class::Schema>.
78 =head2 Using L<DBIx::Class::Loader>
80 This is an additional class, and not part of the L<DBIx::Class>
81 distribution. Like L<Class::DBI::Loader>, it inspects your database,
82 and automatically creates classes for all the tables in your database.
83 Here's a simple setup:
86 use DBIx::Class::Loader;
88 my $loader = DBIx::Class::Loader->new(
89 dsn => 'dbi:SQLite:/home/me/myapp/my.db',
90 namespace => 'MyApp::DB'
95 This should be equivalent to the manual setup in the section above.
96 L<DBIx::Class::Loader> takes lots of other options. For more
97 information, consult its documentation.
101 Once you've defined the basic classes, either manually or using
102 L<DBIx::Class::Loader>, you can start interacting with your database.
103 The simplest way to get a record is by primary key:
105 my $album = MyApp::DB::Album->find(14);
107 This will run a C<SELECT> with C<albumid = 14> in the C<WHERE> clause,
108 and return an instance of C<MyApp::DB::Album> that represents this
109 row. Once you have that row, you can access and update columns:
111 $album->title('Physical Graffiti');
112 my $title = $album->title; # $title holds 'Physical Graffiti'
114 If you prefer, you can use the C<set_column> and C<get_column>
117 $album->set_column('title', 'Presence');
118 $title = $album->get_column('title');
120 Just like with L<Class::DBI>, you do an C<update> to commit your
121 changes to the database:
125 If needed, you can throw away your local changes like this:
127 $album->discard_changes if $album->is_changed;
129 As you can see, C<is_changed> allows you to check if there are local
130 changes to your object.
132 =head2 Adding and removing rows
134 To create a new record in the database, you can use the C<create>
135 method. It returns an instance of C<MyApp::DB::Album> that can be
136 used to access the data in the new record:
138 my $new_album = MyApp::DB::Album->create({
139 title => 'Wish You Were Here',
140 artist => 'Pink Floyd'
143 Now you can add data to the new record:
145 $new_album->label('Capitol');
146 $new_album->year('1975');
149 Likewise, you can remove it from the database like this:
153 You can also remove records without or retrieving first. This
154 operation takes the same kind of arguments as a search.
156 # Delete all of Falco's albums
157 MyApp::DB::Album->delete({ artist => 'Falco' });
159 =head2 Finding your objects
161 L<DBIx::Class> provides a few different ways to retrieve data from
162 your database. Here's one example:
164 # Find all of Santana's albums
165 my $rs = MyApp::DB::Album->search({ artist => 'Santana' });
167 In scalar context, as above, C<search> returns a
168 L<DBIx::Class::ResultSet> object. It can be used to peek at the first
169 album returned by the database:
171 my $album = $rs->first;
174 Or, you can loop over the albums and update each one:
176 while (my $album = $rs->next) {
177 print $album->artist . ' - ' . $album->title;
182 For more information on what you can do with a
183 L<DBIx::Class::ResultSet>, see L<DBIx::Class::ResultSet/METHODS>.
185 In list context, the C<search> method returns all of the matching
188 # Fetch immediately all of Carlos Santana's albums
189 my @albums = MyApp::DB::Album->search({ artist => 'Carlos Santana' });
190 foreach my $album (@albums) {
191 print $album->artist . ' - ' . $album->title;
194 We also provide a handy shortcut for doing a C<LIKE> search:
196 # Find albums whose artist starts with 'Jimi'
197 my $rs = MyApp::DB::Album->search_like({ artist => 'Jimi%' });
199 Or you can provide your own handmade C<WHERE> clause, like:
201 # Find Peter Frampton albums from the year 1986
202 my $where = 'artist = ? AND year = ?';
203 my @bind = ( 'Peter Frampton', 1986 );
204 my $rs = MyApp::DB::Album->search_literal( $where, @bind );
206 The preferred way to generate complex queries is to provide a
207 L<SQL::Abstract> construct to C<search>:
209 my $rs = MyApp::DB::Album->search({
210 artist => { '!=', 'Janis Joplin' },
211 year => { '<' => 1980 },
212 albumid => [ 1, 14, 15, 65, 43 ]
215 This results in something like the following C<WHERE> clause:
217 WHERE artist != 'Janis Joplin'
219 AND albumid IN (1, 14, 15, 65, 43)
221 For more examples of complex queries, see
222 L<DBIx::Class::Manual::Cookbook>.
224 The search can also be modified by passing another hash with
227 my @albums = MyApp::DB::Album->search(
228 { artist => 'Bob Marley' },
229 { rows => 2, order_by => 'year DESC' }
232 C<@albums> then holds the two most recent Bob Marley albums.
234 For a complete overview of the available attributes, see
235 L<DBIx::Class::ResultSet/ATTRIBUTES>.
241 =item * L<DBIx::Class::Manual::Cookbook>
243 =item * L<DBIx::Class::Manual::FAQ>