The following additional rules apply to field names:
A field name can be defined more than once if each definition using that name has the same data type, the same length, and the same number of decimal positions. All definitions using the same name refer to a single field (that is, the same area in storage). However, it can be defined only once on the definition specification.
A field can be defined as a data structure subfield only once unless the data structure is qualified (defined with QUALIFIED or LIKEDS). In this case, when the subfield is used, it must be qualified (specified in the form dsname.subfieldname).
A subfield name cannot be specified as the result field on an *ENTRY PLIST parameter.