CNC-312 Foundations of Information Systems Lec 5: Transaction Management Overview
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Questions and Answers

Which of the following best describes the concept of 'Atomicity' in the context of transactions?

  • Only a subset of actions in the transaction are executed
  • Either all actions of the transaction are executed or none at all (correct)
  • All actions of the transaction are executed in any order
  • Some actions of the transaction may be executed while others are not

    • What does the 'Isolation' property ensure in the context of transactions?

  • Transactions are allowed to directly modify data from other transactions
  • Transactions have no impact on the overall database consistency
  • Transactions are guaranteed to be executed in a serial manner
  • Transactions are protected from effects of concurrently running transactions (correct)

    • What is the primary role of the DBMS in achieving concurrency for transactions?

  • Allowing transactions to directly modify database objects
  • Interleaving actions of various transactions to achieve the same effect as serial execution (correct)
  • Preventing multiple transactions from executing at the same time
  • Enforcing a strict serial execution of transactions

    • In the context of transactions, what does 'Durability' ensure?

    <p>Effects of committed transactions must persist and overcome any system failure</p> Signup and view all the answers

    How does the 'Consistency' property relate to a transaction's impact on the database state?

    <p>A transaction must leave the database in a consistent state upon completion</p> Signup and view all the answers

    What is the DBMS's primary concern with regard to a user's program involving transactions?

    <p>The data read/written from/to the database during the user's program</p> Signup and view all the answers

    What is the main purpose of the DBMS log in relation to atomicity?

    <p>To record all actions, allowing the DBMS to undo actions of aborted transactions.</p> Signup and view all the answers

    What is the primary role of durability in a DBMS?

    <p>Ensure that committed actions are written to disk or can be redone if not yet written to disk in case of a crash.</p> Signup and view all the answers

    What is the purpose of concurrent execution of user programs in a DBMS?

    <p>To increase system throughput by overlapping I/O and CPU operations.</p> Signup and view all the answers

    What is the characteristic of a serial schedule in DBMS?

    <p>It does not interleave the actions of different transactions.</p> Signup and view all the answers

    What defines a serializable schedule in a DBMS?

    <p>A schedule that is equivalent to some serial execution of the transactions on any consistent database instance.</p> Signup and view all the answers

    Why is concurrent execution of transactions important for good DBMS performance?

    <p>It increases system throughput by overlapping I/O and CPU operations.</p> Signup and view all the answers

    In the context of concurrency control, what does a schedule refer to?

    <p>A list of actions from a set of transactions as seen by the DBMS.</p> Signup and view all the answers

    What is the primary goal of scheduling transactions in a DBMS?

    <p>To create an actual or potential execution sequence while maintaining consistency.</p> Signup and view all the answers

    What is the significance of equivalent schedules in a DBMS?

    <p>They guarantee that the effect of executing one schedule is identical to the effect of executing another schedule for any database state.</p> Signup and view all the answers

    What represents a major challenge for a DBMS during concurrent execution of transactions?

    <p>Coping with effects of interleaving transactions (Concurrency control).</p> Signup and view all the answers

    What role does the DBMS log play in ensuring atomicity during transaction processing?

    <p>To record all actions, allowing the DBMS to undo actions of aborted transactions.</p> Signup and view all the answers

    Which property of a transaction ensures that the effects of committed transactions must persist and overcome any system failure?

    <p>Durability</p> Signup and view all the answers

    In the context of transactions, which property protects a transaction from the effects of concurrently running transactions?

    <p>Isolation</p> Signup and view all the answers

    What is the primary concern of the DBMS in achieving concurrency for transactions?

    <p>Managing scheduling</p> Signup and view all the answers

    Which characteristic of a transaction ensures that either all actions of the transaction are executed or none at all?

    <p>Atomicity</p> Signup and view all the answers

    What is the significance of equivalent schedules in a DBMS?

    <p>They produce the same net effect as serial execution of transactions.</p> Signup and view all the answers

    In the context of scheduling transactions in a DBMS, what represents a major challenge during concurrent execution?

    <p>Preventing transaction interference</p> Signup and view all the answers

    Which feature of the DBMS ensures that committed actions are written to disk or, in case of a crash, the system must redo actions of committed transactions which were not yet written to disk?

    <p>Durability</p> Signup and view all the answers

    What is the primary reason for the DBMS to log all actions of a transaction?

    <p>To ensure atomicity of transactions</p> Signup and view all the answers

    In the context of concurrent execution of transactions, what is the main purpose of overlapping I/O and CPU operations?

    <p>Improving system throughput</p> Signup and view all the answers

    Which characteristic defines a serializable schedule in a DBMS?

    <p>Equivalent to some serial execution of the transactions on any consistent database instance</p> Signup and view all the answers

    What represents a major challenge for a DBMS during concurrent execution of transactions?

    <p>Handling interleaving transactions</p> Signup and view all the answers

    What is the primary role of concurrency control in a DBMS?

    <p>Ensuring data consistency</p> Signup and view all the answers

    In the context of transactions, what does 'Atomicity' ensure?

    <p>All or nothing transaction processing</p> Signup and view all the answers

    What is the main reason for maintaining equivalent schedules in a DBMS?

    <p>Ensuring database consistency</p> Signup and view all the answers

    What role does the DBMS log play in ensuring atomicity during transaction processing?

    <p>Undoing actions of aborted transactions</p> Signup and view all the answers

    In the context of concurrency control, what does a schedule refer to?

    <p>A list of actions from a set of transactions as seen by DBMS</p> Signup and view all the answers

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