FairCom RTG provides a command-line switch to the ctutil utility (ctutil -ddf2xdd) to convert DDF files into an XDD (eXtended Data Definition) file. This file is in XML format and contains information about the data and index structures including: index definitions, record schemas, default field values, null field handling, behavior of data conversion errors, etc.
During the conversion from DDF to XDD, ctutil also accepts a “rule file” that contains instructions to customize the generated XDD file for specific needs (such as default values for fields).