Ü  Difference between CHAIN and SETLL

·         The CHAIN operation applies a record lock to files that are open or update. The SETLL operation does not apply the lock.

·         The CHAIN operation copies the record's data to the input buffer for the program. The SETLL operation does not.

·         If we just want to check for the existence of the record, then SETLL is better option as CHAIN will put an extra overhead in copying the data to input buffer.

·         In CHAIN random access operation is performed, while in SETLL READ EQUAL OR LESS operation is performed.

·         Resulting indicator in case of CHAIN will be HI, while in case of SETLL the operation will be EQ.

·         CHAIN operation returns the returns only if there is an exact match for the key/RRN specified in factor-1, but in case of SETLL even there is not exact match the greater key value matching record will be positioned.