Two-Phase Locking (2PL) is a concurrency-control protocol used in Database Management Systems to ensure that multiple transactions can execute simultaneously without producing inconsistent or incorrect results. It controls concurrent access to shared data items by using locks. A transaction must obtain an appropriate lock before reading or writing a data item. The two main types of locks are shared lock (S-lock), which permits reading, and exclusive lock (X-lock), which is required for writing. The 2PL protocol divides the execution of a transaction into two phases: the growing phase and the shrinking phase. During the growing phase, a transaction can acquire new locks but cannot release any lock. During the shrinking phase, it can release locks but cannot acquire any new lock. This rule ensures that transactions follow a controlled ordering of conflicting operations and provides conflict serializability. For example, suppose two transactions, T1 and T2, access the same analytical data item X. T1 wants to increase X by 50, while T2 wants to increase X by 20 percent. Before T1 reads X, it obtains an S-lock on X. Because T1 later needs to modify X, it must obtain an X-lock before writing. Similarly, T2 must obtain an appropriate lock before reading or modifying X. If T1 has