A transaction may be in one of the following states during its execution life cycle in concurrent execution environment. A. FAILED B. TERMINATED C. PARTIALLY COMMITTED D. COMMITTED E. ACTIVE Given a transaction in active state during its execution, find its next transitioned state from the options given below :
Either A or C only
An active transaction moves to partially committed after its final statement completes, or to failed if execution cannot continue successfully. Commitment follows successful completion of the commit protocol; a failure requires rollback before the transaction is aborted. Thus the immediate next state is either A or C.
Important Questions from States of Transaction - Teaching
Which of the DBMS component ensures that concurrent execution of multiple operations on the database results into a consistent database state?
Consider the following sequence of two transactions on a bank account(A) with initial balance 20,000 that transfers 5,000 to another account (B) and then apply 10% interest.
(i) T1 start
(ii) T1 A old = 20000 new 15,000
(iii) T1 B old = 12000 new = 17000
(iv) T1 commit
(v) T2 start
(vi) T2 A old = 15000 new = 16500
(vii) T2 commit
Suppose the database system crashes out just before log record (vii) is written. When the system is restricted, which one statement is true of the recovery process?A restaurant ordering system is modelled with a UML sequence diagram. Use exactly one lifeline for each distinct named participant in the following exchanges; do not merge participants or add lifelines for message parameters.
1. Customer sends placeOrder to OrderController.
2. OrderController sends prepareOrder to Kitchen.
3. Kitchen sends orderReady to Server.
4. Server sends serveItems to Customer.
5. Customer sends requestBill to Server.
6. Server sends prepareBill to BillingService.
7. BillingService returns the bill to Server, which presents it to Customer.
8. Customer sends payBill to BillingService.
How many lifelines represent the participants in this specified diagram?
