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Class::DBI::Loader::Relationship - Easier relationship specification in CDBI::L


  use Class::DBI::Loader::Relationship;

  my $loader = Class::DBI::Loader->new( dsn => "mysql:beerdb",
                                        namespace => "BeerDB");

Now instead of saying

    BeerDB::Brewery->has_many(beers => "BeerDB::Beer");
    BeerDB::Beer->has_a(brewery => "BeerDB::Brewery");

    BeerDB::Handpump->has_a(beer => "BeerDB::Beer"); 
    BeerDB::Handpump->has_a(pub => "BeerDB::Pub");
    BeerDB::Pub->has_many(beers => [ BeerDB::Handpump => 'beer' ]);
    BeerDB::Beer->has_many(pubs => [ BeerDB::Handpump => 'pub' ]);

Just say

    $loader->relationship( "a brewery produces beers" );
    $loader->relationship( "a pub has beers on handpumps" );


This module acts as a mix-in, adding the relationship method to Class::DBI::Loader. Since Class::DBI::Loader knows how to map between table names and class names, there ought to be no need to replicate the names.

In addition, it is common (but not universal) to want reverse relationships defined for has-many relationships, and for has-a relationships to be defined for the linkages surrounding a many-to-many table.

The aim of CDBIL::Relationship is to simplify the declaration of common database relationships by providing both of these features.

The relationship takes a string. It recognises table names (singular or plural, for convenience) and extracts them from the "sentence".


Simon Cozens,