How to create Data Definition Files (.DDF) files to work with third-party products that requires them?

How to create Data Definition Files (.DDF) files to work with third-party products that requires them?

The .DDF file can be obtained in two ways;
- The vendor of the product should be able to provide .DDF along with the software.
- Or, use Xtrieve PLUS,XQL or NetWare SQL for creating the .DDF file.