When the description of an externally described file is retrieved by the compiler, the record definitions are also retrieved. To refer to the record definitions, specify the record format name in the input, calculation, and output specifications of the program. Input specifications for an externally described file are required if:
The field description specifications must immediately follow the record identification specification for an externally described file.
A record line for an externally described file defines the beginning of the override specifications for the record. All specifications following the record line are part of the record override until another record format name or file name is found in positions 7 through 16 of the input specifications. All record lines that pertain to an externally described file must appear together; they cannot be mixed with entries for other files.