COBOL Manual for TNS/E Programs (H06.08+, J06.03+)

DYNAMIC
makes the access mode of the file dynamic. That means the records of the file are accessible
by either sequential or random access; you can position the file with START to a certain
key value and read or write sequentially from there. The default access mode is sequential.
RECORD KEY clause
rec-key
is an alphanumeric or unsigned numeric data item defined in the record description entry
for the file. It is the prime key for accessing records within the file. If the file was created
with FUP or CREATE, the reckey size and location must agree with the size and location
of the prime key established by FUP or CREATE.
All records in the file are ranked in ascending order of the reckey value, which must be
unique for each record.
ALTERNATE RECORD KEY clause
makes alt-key an alternate record key.
alt-key
is an alphanumeric or unsigned numeric data item declared in the record description entry
of the file and is used to gain access to records within the file. The alt-key size and
location must agree with the size and location of the alternate key within the file, as defined
when the alternate key file was established by the operating system File Utility Program
(FUP). (For information about FUP, see the File Utility Program (FUP) Reference Manual.)
DUPLICATES
means that alternate key values are not necessarily unique.
FILE STATUS clause
defines filestat as the file-status data item for the file. When a COBOL run-time I-O routine
completes an operation on the file, it stores the status code in filestat before returning
control to your program (see I-O Status Code (page 247)).
filestat
is a 2-character alphanumeric, nonnational data item defined in the Working-Storage
Section, Extended-Storage Section, or Linkage Section.
134 Environment Division