Tran1 reads the value of object X (500) at time t1, writes a new value at a later time, and then rolls back its changes at time t6. Tran2 reads the value of X (600) at time t5, writes a new value, and commits its changes at time t8. This scenario violates the isolation property of database transactions since Tran2 read X after it was updated by Tran1, but before Tran1's changes were rolled back, resulting in an inconsistent view of the data.

1. Q3 - A2 - DATABASE SYSTEMS
Consider a database with object X initially 500 and assume that there are two transactions Tran1
and Tran2. Transaction Tran1 reads object X at time t1 and then writes object X and later rollback
at time t6. Transaction Tran2 reads object X at time t5 as 600 and then writes object X and finally
commit object X at time t8. That is, t1 T1:R(X), W(X); t5T2: R(X), W(X), Commit(X); t6 Tran1
Rollback; t8Tran2 Commits.
i. State and explain the above concurrent access problem scenario? 10 Marks)
ii. How best can the above problem be prevented, explain using examples? (10 Marks)
iii. Which transaction property is violated, give reasons? (10 Marks)