Class::DBI::BaseDSN - DSN sensitive base class
package My::DBI; use base 'Class::DBI::BaseDSN'; # we'll decide later what our real # parent class will be __PACKAGE__->set_db( Main => $ENV{TESTING} ? @test_dsn : @real_dsn );
Class::DBI::BaseDSN acts as a placeholder for a base class which will be switched for a specific Class::DBI extension when you specify the dsn of the database to connect to.
For example in this case, the Class::DBI::BaseDSN will replace itself
with Class::DBI::mysql when the set_db
call is executed.
package Example::DBI; use base 'Class::DBI::BaseDSN'; __PACKAGE__->set_db( Main => 'dbi:mysql:example', 'user', 'pass' );
Since this happens at runtime you could pass the dsn as a variable and so have it use a completely different extension automatically. This is especially useful for testing, or for applications where dsn may be a configuration option.
If there is no matching extension found, Class::DBI::BaseDSN replaces itself with Class::DBI.
Richard Clamp <richardc@unixbeard.net>
Thanks go to Michael Schwern for a snippet to fake out caller, and for hashing out some of the finer points of the approach on the cdbi-talk list.