References to Data Division Names

Data Division names that are explicitly referenced in a program must be either uniquely defined, or made unique through qualification. Unreferenced data-names need not be uniquely defined.

A data-name associated with a level-number 01, or with an FD or SD level indicator in the File Section, is the highest level in a data hierarchy. If referenced, it must be uniquely defined, because it cannot be qualified. Data items with level-numbers 02 through 49 are successively lower levels in a data hierarchy, and if referenced, must be either uniquely defined, or made unique through qualification. Level-77 data-names, if referenced, must be uniquely defined, because they cannot be qualified.