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.
Perl modules are notated in many different formats: "Foo/Bar/Baz.pm", "Foo::Bar", "Foo-Bar", etc. Module-Format allows one to take a list of modules in any format (including mixed ones) and output it in a consistent format that can be input to an installation program or an information querier.