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

ORGANIZATION clause
makes the organization of the file relative. (The default is sequential.)
ACCESS MODE clause
SEQUENTIAL
makes the access mode of the file sequential (the default). That means the records of the
file are to be operated upon as if they were sequentially organized.
RANDOM
makes the access mode of the file random. That means the records of the file are to be
operated upon in any order, as selected by the current value of the relative key or an
alternate key.
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 to a certain key value with
START and read or write sequentially from there.
RELATIVE KEY clause
rel-key
is an integer data item to be used as a prime key to specify records within the file. It must
be large enough to hold the maximum record number. Its definition cannot be in a record
description entry for that file. It can be in another record description entry or in the
Working-Storage Section, Extended-Storage Section, or Linkage Section.
ALTERNATE RECORD KEY clause
Input-Output Section 129