Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Database-Management-System
| Question 501 |
Which of the following statement is wrong ?
I. 2-phase locking protocol suffer from deadlock.
II. Time stamp protocol suffer from more aborts.
III. A block hole in a DFD is a data store with only inbound flows.
IV. Multivalued dependency among attribute is checked at 3 NF level.
V. An entity-relationship diagram is a tool to represent event model.
I. 2-phase locking protocol suffer from deadlock.
II. Time stamp protocol suffer from more aborts.
III. A block hole in a DFD is a data store with only inbound flows.
IV. Multivalued dependency among attribute is checked at 3 NF level.
V. An entity-relationship diagram is a tool to represent event model.
| I, II, II | |
| II, III, IV | |
| III, IV, V | |
| II, IV, V |
Question 501 Explanation:
ER- model: This model and its variations are frequently used for the conceptual design of database applications, and many database design tools employ its concepts. Hence statement 5 is wrong.
3NF: This normal form is responsible for checking transitive dependency. It is 4NF which checks multivalued dependency. Hence statement 4 is wrong.
2-Phase locking: It provides a serializable schedule but does not provides a deadlock free serializable schedule. Deadlock might occur using this concurrency control mechanism.
Time Stamp Protocol: It suffers more aborts in comparison of other concurrency control protocols because of allowing the execution of the transactions based upon their time stamp ordering. A transaction with higher timestamp is allowed to execute otherwise if a transaction with lower timestamp requests for execution then in that case that transaction will be aborted.
Hence only option A is correct.
3NF: This normal form is responsible for checking transitive dependency. It is 4NF which checks multivalued dependency. Hence statement 4 is wrong.
2-Phase locking: It provides a serializable schedule but does not provides a deadlock free serializable schedule. Deadlock might occur using this concurrency control mechanism.
Time Stamp Protocol: It suffers more aborts in comparison of other concurrency control protocols because of allowing the execution of the transactions based upon their time stamp ordering. A transaction with higher timestamp is allowed to execute otherwise if a transaction with lower timestamp requests for execution then in that case that transaction will be aborted.
Hence only option A is correct.
Correct Answer: A
Question 501 Explanation:
ER- model: This model and its variations are frequently used for the conceptual design of database applications, and many database design tools employ its concepts. Hence statement 5 is wrong.
3NF: This normal form is responsible for checking transitive dependency. It is 4NF which checks multivalued dependency. Hence statement 4 is wrong.
2-Phase locking: It provides a serializable schedule but does not provides a deadlock free serializable schedule. Deadlock might occur using this concurrency control mechanism.
Time Stamp Protocol: It suffers more aborts in comparison of other concurrency control protocols because of allowing the execution of the transactions based upon their time stamp ordering. A transaction with higher timestamp is allowed to execute otherwise if a transaction with lower timestamp requests for execution then in that case that transaction will be aborted.
Hence only option A is correct.
3NF: This normal form is responsible for checking transitive dependency. It is 4NF which checks multivalued dependency. Hence statement 4 is wrong.
2-Phase locking: It provides a serializable schedule but does not provides a deadlock free serializable schedule. Deadlock might occur using this concurrency control mechanism.
Time Stamp Protocol: It suffers more aborts in comparison of other concurrency control protocols because of allowing the execution of the transactions based upon their time stamp ordering. A transaction with higher timestamp is allowed to execute otherwise if a transaction with lower timestamp requests for execution then in that case that transaction will be aborted.
Hence only option A is correct.
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