DBIx-Class is an SQL to OO mapper with an object API inspired by Class::DBI (with a compatibility layer as a springboard for porting) and a resultset API that allows abstract encapsulation of database operations. It aims to make representing queries in your code as Perl-ish as possible while still providing access to as many of the capabilities of the database as possible, including retrieving related records from multiple tables in a single query.
Test::Class provides a simple way of creating classes and objects to test your Perl code in an xUnit style. Built using Test::Builder, it was designed to work with other Test::Builder-based modules. You can easily package your tests as classes/modules rather than *.t scripts. This simplifies reuse, documentation, and distribution, encourages refactoring, and allows tests to be extended by inheritance.
Fedora-Bugzilla is a Perl module that aims to expose a kinder, gentler interface to Fedora/RedHat's Bugzilla implementation, which has a large number of custom methods. In addition to the XML-RPC methods that Bugzilla makes available, there are also some things that can be accessed only via the Web/XML interfaces, such as the flags, attachments, and comments functionality. This package works to expose those as well.
XML::RDB is a Perl extension to convert XML files into RDB schemas and populate/unpopulate them. It works with XML schemas too. It analyzes relationships within either an XML file or an XML schema to create RDB tables to hold that document (or any XML document that conforms to the XML schema). It takes an XML file or URL as input for the XML::DOM::Parser, and extracts information to build and write DDL. An attempt is made to recognize relations within the XML structure then translate it to the DDL. That generated DDL is then loaded, parsing the DOM tree a second time to extract and load the data. At the bottom of the DDL are select statements to help get a view of those relations found, and XML data. xml_rdb also dumps the data back to XML format.