UPDATING OF THE RELATIVE AND INDEXED FILES:
The Sequential files are updated by creating a new master file from an existing old master file and a transaction file. Such an Updating is termed as updating by copy. The Direct access files can be updated by the technique termed as Updating by overlay. In this situation no new file is created. Rather than, the essential changes are incorporated in the body of the file.
The transaction code (T-CODE) is a one-digit code having the meaning as shown below: