1
2=head1 NAME
3
4DBIx::Class::Manual::Component - Developing DBIx::Class Components
5
6=head1 WHAT IS A COMPONENT
7
8A component is a module that can be added in to your DBIx::Class
9classes to provide extra functionality. A good example is the PK::Auto
10component which automatically retrieves primary keys that the database
11itself creates, after the insert has happened.
12
13=head1 USING
14
15Components are loaded using the load_components() method within your
16DBIx::Class classes.
17
18  package My::Thing;
19  use base qw( DBIx::Class::Core );
20  __PACKAGE__->load_components(qw/InflateColumn::DateTime TimeStamp/);
21
22Generally you do not want to specify the full package name
23of a component, instead take off the DBIx::Class:: part of
24it and just include the rest.  If you do want to load a
25component outside of the normal namespace you can do so
26by prepending the component name with a +.
27
28  __PACKAGE__->load_components(qw/ +My::Component /);
29
30Once a component is loaded all of its methods, or otherwise,
31that it provides will be available in your class.
32
33The order in which is you load the components may be very
34important, depending on the component. If you are not sure,
35then read the docs for the components you are using and see
36if they mention anything about the order in which you should
37load them.
38
39=head1 CREATING COMPONENTS
40
41Making your own component is very easy.
42
43  package DBIx::Class::MyComp;
44  use base qw(DBIx::Class);
45  # Create methods, accessors, load other components, etc.
46  1;
47
48When a component is loaded it is included in the calling
49class' inheritance chain using L<Class::C3>.  As well as
50providing custom utility methods, a component may also
51override methods provided by other core components, like
52L<DBIx::Class::Row> and others.  For example, you
53could override the insert and delete methods.
54
55  sub insert {
56    my $self = shift;
57    # Do stuff with $self, like set default values.
58    return $self->next::method( @_ );
59  }
60
61  sub delete {
62    my $self = shift;
63    # Do stuff with $self.
64    return $self->next::method( @_ );
65  }
66
67Now, the order that a component is loaded is very important.  Components
68that are loaded first are the first ones in the inheritance stack.  So, if
69you override insert() but the DBIx::Class::Row component is loaded first
70then your insert() will never be called, since the DBIx::Class::Row insert()
71will be called first.  If you are unsure as to why a given method is not
72being called try printing out the current linearized MRO.
73
74  print join ', ' => mro::get_linear_isa('YourClass::Name');
75
76=head1 EXISTING COMPONENTS
77
78=head2 Extra
79
80These components provide extra functionality beyond
81basic functionality that you can't live without.
82
83L<DBIx::Class::CDBICompat> - Class::DBI Compatibility layer.
84
85L<DBIx::Class::FormTools> - Build forms with multiple interconnected objects.
86
87L<DBIx::Class::HTMLWidget> - Like FromForm but with DBIx::Class and HTML::Widget.
88
89L<DBIx::Class::Ordered> - Modify the position of objects in an ordered list.
90
91L<DBIx::Class::PK::Auto> - Retrieve automatically created primary keys upon insert.
92
93L<DBIx::Class::QueriesTime> - Display the amount of time it takes to run queries.
94
95L<DBIx::Class::RandomStringColumns> - Declare virtual columns that return random strings.
96
97L<DBIx::Class::UUIDColumns> - Implicit UUID columns.
98
99L<DBIx::Class::WebForm> - CRUD methods.
100
101=head2 Experimental
102
103These components are under development, their interfaces may
104change, they may not work, etc.  So, use them if you want, but
105be warned.
106
107L<DBIx::Class::Validation> - Validate all data before submitting to your database.
108
109=head2 Core
110
111These are the components that all, or nearly all, people will use
112without even knowing it.  These components provide most of
113DBIx::Class' functionality.
114
115L<DBIx::Class::Core> - Loads various components that "most people" would want.
116
117L<DBIx::Class::AccessorGroup> - Lets you build groups of accessors.
118
119L<DBIx::Class::DB> - Non-recommended classdata schema component.
120
121L<DBIx::Class::InflateColumn> - Automatically create objects from column data.
122
123L<DBIx::Class::PK> - This class contains methods for handling primary keys and methods depending on them.
124
125L<DBIx::Class::Relationship> - Inter-table relationships.
126
127L<DBIx::Class::ResultSourceProxy::Table> - Provides a classdata table object and method proxies.
128
129L<DBIx::Class::Row> - Basic row methods.
130
131=head1 SEE ALSO
132
133L<DBIx::Class::Manual::Cookbook>
134
135=head1 FURTHER QUESTIONS?
136
137Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>.
138
139=head1 COPYRIGHT AND LICENSE
140
141This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE>
142by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can
143redistribute it and/or modify it under the same terms as the
144L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>.
145