q3: Draw the state transition diagram and explain the states for transaction execution.

q4:

Explain whether the following transactions T1 and T2 satisfy four variants of 2-Phase Locking protocol (2PL); Basic 2PL, Conservative 2PL, Strict 2PL, and Rigorous 2PL. Write "Yes" or "No", motivate your answers as why or why not and be specific.

T1

LOCK-S(A)

R(A)

LOCK-X(B)

R(A)

R(B)

B=A+B

UNLOCK(A)

W(B)

UNLOCK(B)

T2

LOCK-S(A)

R(A)

LOCK-X(B)

UNLOCK(A)

R(B)

W(B)

COMMIT

UNLOCK(B

(here LOCK-S represents shared lock and LOCK-X represents exclusive lock).

answer:

T1	Basic 2PL	Yes / No: [ Why / Why not ]
	Conservative 2PL	Yes / No: [ Why / Why not ]
	Strict 2PL	Yes / No: [ Why / Why not ]
	Rigorous 2PL	Yes / No: [ Why / Why not ]
T2	Basic 2PL	Yes / No: [ Why / Why not ]
	Conservative 2PL	Yes / No: [ Why / Why not ]
	Strict 2PL	Yes / No: [ Why / Why not ]
	Rigorous 2PL	Yes / No: [ Why / Why not ]