Designates a value for a field that DEC DATATRIEVE recognizes,
       not as the literal value, but as a marker that no value is
       stored in the field. DEC DATATRIEVE ignores fields containing the
       "missing value" marker when evaluating statistical expressions
       (AVERAGE, MAX, MIN, TOTAL, and STD_DEV).

       When you store a record and do not directly assign a value to
       a field with a MISSING VALUE defined, DEC DATATRIEVE uses the
       missing value to initialize the field if it contains no DEFAULT
       VALUE clause.

       Format

         MISSING  [VALUE [IS]] literal