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.
Zero RRD Framework provides a central HTTP-based service for importing into standard RRD databases and for generating graphs. A lightweight, easily extendable agent for the data sources pushes updates with minimal resource consumption to the master service using HTTP. With the introduction of VMs for the service, it's easy to test-drive the application and even the architecture (connecting agents to the service in the VM).
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.