When a transaction Ti attempts to update a data item, it requests a _________ on that data item.
A. Read lock
B. Update lock
C. Write lock
D. Chain lock
Answer:A
When a transaction Ti attempts to update a data item, it requests a _________ on that data item.
A. Read lock B. Update lock C. Write lock D. Chain lock
Explanation: Reads are unaffected by this, since they do not obtain locks.