What is two-phase locking? What are different types of locks in two-phase locking? Explain basic, conservative, strict, rigorous two-phase locking. What is lock conversion?

A transaction is said to follow the two-phase locking (2-PL) protocol if all locking operations (read-lock, write-lock) precede the first unlock operation in the transaction. Locking is an operation which secures permission to read or permission to write a data item. Two-phase locking is a proces...