NAME

       Class::DBI::Relationship - base class for Relationships

DESCRIPTION

       A Class::DBI class represents a database table. But merely being able to represent single
       tables isn't really that useful - databases are all about relationships.

       So, Class::DBI provides a variety of Relationship models to represent common database
       occurences (HasA, HasMany and MightHave), and provides a way to add others.

SUBCLASSING

       Relationships should inherit from Class::DBI::Relationship, and provide a variety of
       methods to represent the relationship. For examples of how these are used see
       Class::DBI::Relationship::HasA, Class::DBI::Relationship::HasMany and
       Class::DBI::Relationship::MightHave.

   remap_arguments
               sub remap_arguments {
                       my $self = shift;
                       # process @_;
                       return ($class, accessor, $foreign_class, $args)
               }

       Subclasses should define a 'remap_arguments' method that takes the arguments with which
       your relationship method will be called, and transforms them into the structure that the
       Relationship modules requires.  If this method is not provided, then it is assumed that
       your method will be called with these 3 arguments in this order.

       This should return a list of 4 items:

       class
           The Class::DBI subclass to which this relationship applies. This will be passed in to
           you from the caller who actually set up the relationship, and is available for you to
           call methods on whilst performing this mapping. You should almost never need to change
           this.

           This usually an entire application base class (or Class::DBI itself), but could be a
           single class wishing to override a default relationship.

       accessor
           The method in the class which will provide access to the results of the relationship.

       foreign_class
           The class for the table with which the class has a relationship.

       args
           Any additional args that your relationship requires.  It is recommended that you use
           this as a hashref to store any extra information your relationship needs rather than
           adding extra accessors, as this information will all be stored in the 'meta_info'.

   triggers
               sub triggers {
                       return (
                               before_create => sub { ... },
                               after_create  => sub { ... },
                       );
               }

       Subclasses may define a 'triggers' method that returns a list of triggers that the
       relationship needs. This method can be omitted if there are no triggers to be set up.

   methods
               sub methods {
                       return (
                               method1 => sub { ... },
                               method2 => sub { ... },
                       );
               }

       Subclasses may define a 'methods' method that returns a list of methods to facilitate the
       relationship that should be created in the calling Class::DBI class.  This method can be
       omitted if there are no methods to be set up.