Describe database files using DDS

When you describe a database file using data description specifications (DDS), you can describe information at the file, record-format, join, field, key, and select/omit levels.

• Example: Describe a physical file using DDS
  This example shows how to describe a physical a file using DDS.
• Example: Describe a logical file using DDS
  This example shows how to describe a logical file using DDS.
• Additional field definition functions you can describe with DDS
  You can describe additional information about the fields in the physical and logical file record formats with function keywords (positions 45 through 80 on the DDS form).
• Use existing field descriptions and field reference files to describe a database file
  If a field was already described in an existing file, and you want to use that field description in a new file you are setting up, you can request the system to copy that description into your new file description.
• Use a data dictionary for field reference in a database file
  You can use a data dictionary and the interactive data description utility (IDDU) as an alternative to using a DDS field reference file. IDDU allows you to define fields in a data dictionary.
• Share existing record format descriptions in a database file
  A record format can be described once in either a physical or a logical file (except a join logical file) and can be used by many files. When you describe a new file, you can specify that the record format of an existing file is to be used by the new file.