NAME¶
DBIx::Class::Manual::Component - Developing DBIx::Class Components
WHAT IS A COMPONENT¶
A component is a module that can be added in to your DBIx::Class classes to
provide extra functionality. A good example is the PK::Auto component which
automatically retrieves primary keys that the database itself creates, after
the insert has happened.
USING¶
Components are loaded using the
load_components() method within your
DBIx::Class classes.
package My::Thing;
use base qw( DBIx::Class::Core );
__PACKAGE__->load_components(qw/InflateColumn::DateTime TimeStamp/);
Generally you do not want to specify the full package name of a component,
instead take off the DBIx::Class:: part of it and just include the rest. If
you do want to load a component outside of the normal namespace you can do so
by prepending the component name with a +.
__PACKAGE__->load_components(qw/ +My::Component /);
Once a component is loaded all of its methods, or otherwise, that it provides
will be available in your class.
The order in which is you load the components may be very important, depending
on the component. If you are not sure, then read the docs for the components
you are using and see if they mention anything about the order in which you
should load them.
CREATING COMPONENTS¶
Making your own component is very easy.
package DBIx::Class::MyComp;
use base qw(DBIx::Class);
# Create methods, accessors, load other components, etc.
1;
When a component is loaded it is included in the calling class' inheritance
chain using Class::C3. As well as providing custom utility methods, a
component may also override methods provided by other core components, like
DBIx::Class::Row and others. For example, you could override the insert and
delete methods.
sub insert {
my $self = shift;
# Do stuff with $self, like set default values.
return $self->next::method( @_ );
}
sub delete {
my $self = shift;
# Do stuff with $self.
return $self->next::method( @_ );
}
Now, the order that a component is loaded is very important. Components that are
loaded first are the first ones in the inheritance stack. So, if you override
insert() but the DBIx::Class::Row component is loaded first then your
insert() will never be called, since the DBIx::Class::Row
insert() will be called first. If you are unsure as to why a given
method is not being called try printing out the current linearized MRO.
print join ', ' => mro::get_linear_isa('YourClass::Name');
EXISTING COMPONENTS¶
These components provide extra functionality beyond basic functionality that you
can't live without.
DBIx::Class::CDBICompat - Class::DBI Compatibility layer.
DBIx::Class::FormTools - Build forms with multiple interconnected objects.
DBIx::Class::HTMLWidget - Like FromForm but with DBIx::Class and HTML::Widget.
DBIx::Class::Ordered - Modify the position of objects in an ordered list.
DBIx::Class::PK::Auto - Retrieve automatically created primary keys upon insert.
DBIx::Class::QueriesTime - Display the amount of time it takes to run queries.
DBIx::Class::RandomStringColumns - Declare virtual columns that return random
strings.
DBIx::Class::UUIDColumns - Implicit UUID columns.
DBIx::Class::WebForm - CRUD methods.
Experimental¶
These components are under development, their interfaces may change, they may
not work, etc. So, use them if you want, but be warned.
DBIx::Class::Validation - Validate all data before submitting to your database.
Core¶
These are the components that all, or nearly all, people will use without even
knowing it. These components provide most of DBIx::Class' functionality.
DBIx::Class::Core - Loads various components that "most people" would
want.
DBIx::Class::AccessorGroup - Lets you build groups of accessors.
DBIx::Class::DB - Non-recommended classdata schema component.
DBIx::Class::InflateColumn - Automatically create objects from column data.
DBIx::Class::PK - This class contains methods for handling primary keys and
methods depending on them.
DBIx::Class::Relationship - Inter-table relationships.
DBIx::Class::ResultSourceProxy::Table - Provides a classdata table object and
method proxies.
DBIx::Class::Row - Basic row methods.
SEE ALSO¶
DBIx::Class::Manual::Cookbook
AUTHOR¶
Aran Clary Deltac <bluefeet@cpan.org>