Example of Duplicate Key Definition

To define a duplicate key:

 file control.
     select fd-name
         assign to "user.dat"
         organization is indexed
         record key is fd-name-key
         alternate record key is fd-name-alt-key 
          with duplicates.
    ...
 fd fd-name.
 01 fd-name-record.
     03 fd-name-key     pic X(5).
     03 fd-name-alt-key pic X(4).