Methods of Data Reference

References to data and procedures can be either explicit or implicit.

Every user-defined name in a COBOL program names a resource for solving a data processing problem. To use a resource, a statement in a COBOL program must contain a reference that uniquely identifies that resource. To ensure uniqueness of reference, a user-defined name can be qualified, subscripted, or reference modified. Before looking at this, however, you need to understand the term identifier.