XORT is a utility written in Perl that can be used to read to and write from a relational schema using XML as an interchange format. In GMOD XORT is frequently used to transfer data to and from the Chado schema.
Chado-XML is a direct mapping of the Chado relational schema into XML.
The basic chado-xml expansion can be extremely verbose - this is because chado-xml uses the unique keys from the chado db, yet it does not database internal foreign keys. XORT can be configured with macros that can be used to capture repeated nodes in the XML and give them XML IDs that are valid within a particular document.