Define all your fields first in the field reference file of your application and refer to them whenever you can: in the database specifications, in device file specifications, and in the high-level language programs. This technique helps you to define the field specifications once and use them again.
If you need to distinguish between the same field of different sources, you can rename or qualify them. Whenever you need to change the definition of a specific field, you just need to change the attributes of that field in the field reference file and create the objects again. Then the changes take place automatically in all the different places where the field is used.
For example:
|...+....1....+....2....+....3....+....4....+....5....+....6....+....7....+....8
A REF(field-ref-file-name)
A R record
A field R line pos
or
A field R line pos REFFLD(ref-field-name)