Data Base Management System | Week 7
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These are Data Base Management System Week 7 Assignment Answers
Q1. Consider the following schedule 8 of transactions T1 and T2.
The read operation on data item A is denoted by read(A) and the write operation on data item A is denoted by write (A).
Which of the following is TRUE about the schedule S?
a) S is serializable both as T1, T2 and T2, T1.
b) S is not serializable neither as T1, T2 nor T2, T1.
c) S is serializable only as T1, T2.
d) S is serializable only as T2, T1.
Answer: a) S is serializable both as T1, T2 and T2, T1.
These are Data Base Management System Week 7 Assignment Answers
Q2. Consider the following schedule S involving six transactions T1, T2, T3, T4, T5 and T6 :
R(X) denotes read operation on data item X by transaction Ti.
W(X) denotes write operation on data item X by transaction Ti.
Choose the correct option for the above transaction schedule.
a) The schedule is only view serializable schedule.
b) The schedule is only conflict serializable schedule.
c) The schedule is both view and conflict serializable schedule.
d) The schedule is neither conflict serializable nor view serializable schedule.
Answer: c) The schedule is both view and conflict serializable schedule.
These are Data Base Management System Week 7 Assignment Answers
Q3. Consider the following schedule S involving four transactions T1, T2, T3 and T4.
R(X) denotes read operation on data item X by transaction Ti.
W(X) denotes write operation on data item X by transaction Ti.
Identify the possible number of conflict serializable schedules of the above schedule S.
a) 1
b) 2
c) 3
d) 4
Answer: a) 1
These are Data Base Management System Week 7 Assignment Answers
Q4. Consider the following schedule S.
R(Y) denotes read operation on data item Y by Transaction Ti.
W(Y) denotes write operation on data item Y by Transaction T₁.
Identify the possible number of view serializable schedule of the above schedule S.
a) 1
b) 2
c) 3
d) 4
Answer: d) 4
These are Data Base Management System Week 7 Assignment Answers
Q5. Suppose in a database, there are four transactions T₁, T2, T3 and T₁. Transaction T₁ is waiting for transactions T₂ and T4, transaction T₂ is waiting for transaction T3 and T₁, and transaction T3 is waiting for transactions T4 to release a data item. Identify the correct wait-for graph for the above scenario.
Answer: b
Q6. Consider two transactions given below where lock-X(A) denotes T; has obtained an Exclusive-mode lock on item A and lock-S(A) denotes Ti has obtained a Shared-mode lock on item A.
Which of the following statement is (are) true?
a) Both T₁ and T₂ follow the rigorous two-phase locking protocol.
b) Both T₁ and T2 do not follow the rigorous two-phase locking protocol.
c) Only T₁ follows the rigorous two-phase locking protocol.
d) Only T₂ follows the rigorous two-phase locking protocol.
Answer: c) Only T₁ follows the rigorous two-phase locking protocol.
These are Data Base Management System Week 7 Assignment Answers
Q7. Suppose in a database, there are three transactions T₁, T2 and T3 with timestamp 12, 14 and 16 respectively. T₁ is holding a data item which T2 and T3 are requesting to acquire. Which of the following statement(s) is (are) correct in respect of Wound-Wait Deadlock Prevention scheme?
a) Transaction T₂ will wait for T₁ to release the data item.
b) Transaction T3 will wait for T₁ to release the data item.
c) Transaction T₂ will be aborted.
d) Transaction T3 will be aborted.
Answer: b, c
These are Data Base Management System Week 7 Assignment Answers
Q8. Consider the following schedule S.
R(Y) denotes read operation on data item Y by Transaction Ti.
W(Y) denotes write operation on data item Y by Transaction Ti.
Identify the correct statement(s) based on the above schedule S.
a) If T1 fails (aborted), only T2 must be rolled back.
b) If T1 fails (aborted), only T3 must be rolled back.
c) If T1 fails (aborted), both T2 and T3 must be rolled back.
d) If T1 fails (aborted), neither T2 nor T3 must be rolled back.
Answer: d) If T1 fails (aborted), neither T2 nor T3 must be rolled back.
These are Data Base Management System Week 7 Assignment Answers
Q9. Consider the following schedule S.
R(X) denotes read operation on data item X by Transaction Ti.
W(X) denotes write operation on data item X by Transaction T₁.
Choose the correct options for the above schedule.
a) The schedule is only recoverable schedule.
b) The schedule is only cascadeless schedule.
c) The schedule is recoverable schedule and cascadeless schedule both.
d) The schedule is neither recoverable nor cascadeless schedule.
Answer: a) The schedule is only recoverable schedule.
These are Data Base Management System Week 7 Assignment Answers
Q10. Identify the correct option(s) which is (are) used in Transaction Control Language (TCL).
a) Alter
b) Insert
c) Update
d) Savepoint
Answer: d) Savepoint
These are Data Base Management System Week 7 Assignment Answers
These are Data Base Management System Week 7 Assignment Answers
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