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DBIx::Class::Manual::Component
Developing DBIx::Class Components

DBIx::Class::Manual::Component - Developing DBIx::Class Components


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 );

  __PACKAGE__->load_components(qw/ PK::Auto Core /);

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 it's 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. The general rule of thumb is to first load extra components and then load core ones last. 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 the Class::C3 manpage. As well as providing custom utility methods, a component may also override methods provided by other core components, like the DBIx::Class::Row manpage 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 Class::C3 inheritance stack.


  print join ', ' => Class::C3::calculateMRO('YourClass::Name');

Check out the the Class::C3 manpage docs for more information about inheritance.


EXISTING COMPONENTS

Extra

These components provide extra functionality beyond basic functionality that you can't live without.

the DBIx::Class::CDBICompat manpage - Class::DBI Compatibility layer.

the DBIx::Class::FormTools manpage - Build forms with multiple interconnected objects.

the DBIx::Class::HTMLWidget manpage - Like FromForm but with DBIx::Class and HTML::Widget.

the DBIx::Class::Ordered manpage - Modify the position of objects in an ordered list.

the DBIx::Class::PK::Auto manpage - Retrieve automatically created primary keys upon insert.

the DBIx::Class::QueriesTime manpage - Display the amount of time it takes to run queries.

the DBIx::Class::RandomStringColumns manpage - Declare virtual columns that return random strings.

the DBIx::Class::UTF8Columns manpage - Force UTF8 (Unicode) flag on columns.

the DBIx::Class::UUIDColumns manpage - Implicit UUID columns.

the DBIx::Class::WebForm manpage - CRUD methods.

Experimental

These components are under development, there interfaces may change, they may not work, etc. So, use them if you want, but be warned.

the DBIx::Class::Serialize manpage - Hooks for Storable freeze/thaw.

the DBIx::Class::Serialize::Storable manpage - Hooks for Storable freeze/thaw.

the DBIx::Class::Validation manpage - 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.

the DBIx::Class::AccessorGroup manpage - Lets you build groups of accessors.

the DBIx::Class::Core manpage - Loads various components that ``most people'' would want.

the DBIx::Class::DB manpage - Non-recommended classdata schema component.

the DBIx::Class::InflateColumn manpage - Automatically create objects from column data.

the DBIx::Class::PK manpage - This class contains methods for handling primary keys and methods depending on them.

the DBIx::Class::Relationship manpage - Inter-table relationships.

the DBIx::Class::ResultSourceProxy::Table manpage - Provides a classdata table object and method proxies.

the DBIx::Class::Row manpage - Basic row methods.


SEE ALSO

the DBIx::Class::Manual::Cookbook manpage


AUTHOR

Aran Clary Deltac <bluefeet@cpan.org>

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