The Big Picture

• Creation of Master file: A sequential file containing initial input data must be sorted
• Master File Extension Name in RM/COBOL-85: *.IXF
• Transaction file: Batch data to be used for updating the "Master" indexed file. Contains all changes that have occured since "Master" was created or last updated. It is not required to be sorted by a "key" field.
• On-line interactive updating is possible

Basic Operations

• to create an indexed file - WRITE
• to get a record from an indexed file - READ
• to update a record - REWRITE
• to delete a record - DELETE
• to add a record - WRITE