Data Names and Identifiers:
The Data name provides reference to the storage space in the memory where the real value is stored. This value takes part in the operation whenever that specific data name is used in the Procedure Division.
The Identifier is a general term that means the single data name or a data name qualified, indexed or subscripted. The Data names are only one form of the identifiers. The data name should be a user-defined word and it cannot be a reserved word.
Valid Data Names Invalid Data Names
NET-SALARY COMPUTE (Reserved word)
TOT-MARK MULTIPLY (Reserved word)
N100 23 (No letter)