INF3703-17-S1-1E Self Assessments, Latest complete solutions Questions & Answers (2020).

INF3703-17-S1-1E Self Assessments Chapter 12 Assessment Part 1 of 2 True or False Questions Question 1 of 30 Most real-world database transactions are formed by only one database request. 1. True 2. False Question 2 of 30 Atomicity indicates the permanence of the database's consistent state. 1. True 2. False Question 3 of 30 Durability requires that all portions of the transaction must be treated as a single, logical unit of work in which all operations are applied and completed to produce a consistent database. 1. True 2. False Question 4 of 30 The phenomenon of uncommitted data occurs when two transactions are executed concurrently and the first transaction is rolled back after the second transaction has already accessed the uncommitted data—thus violating the isolation property of transactions. 1. True 2. False Question 5 of 30 Incomplete or improper transactions can have a devastating effect on database integrity. 1. True 2. False Question 6 of 30 The scheduler establishes the order in which the operations within concurrent transactions are executed. 1. True 2. False Question 7 of 30 When using an optimistic approach, a transaction reads the database, executes the needed computations, and makes the updates to a private copy of the database values. 1. True 2. False INF3703-17-S1-1E Self Assessments Question 8 of 30 When using an optimistic approach, during the write phase, the transaction is validated to ensure that the changes made will not affect the integrity and consistency of the database. 1. True 2. False Question 9 of 30 The transaction recovery write-ahead-log protocol ensures that transaction logs are always written before any database data are actually updated 1. True 2. False Question 10 of 30 The last step in the write-through technique recovery procedure is to identify the last checkpoint in the transaction log. 1. True 2. False Question 11 of 30 Concurrency control allows a database to be restored from an inconsistent state to a previously consistent state. 1. True 2. False Question 12 of 30 Database checkpoints are operations in which the DBMS writes all of its updated buffers to disk. While this is happening, the DBMS does not execute any other requests. 1. True 2. False Question 13 of 30 Transaction isolation means that the data used during the execution of a transaction cannot be used by a second transaction until the first one is completed. In other words, if transaction T1 is being executed and is using the data item X, that data item cannot be accessed by any other transaction (T2 ... Tn) until T1 ends. 1. True 2. False Question 14 of 30 Concurrency control is important because the simultaneous execution of transactions over a shared database can create several data integrity and consistency problems. 1. True 2. False INF3703-17-S1-1E Self Assessments Question 15 of 30 To ensure consistency of the database, every transaction must begin with the database in an unstable state. 1. True 2. False Part 2 of 2 - Multiple Choice Questions Question 16 of 30 What is a rule that applies to the two-phase locking protocol? A. Two transactions cannot have conflicting locks. B. No unlock operation can precede a lock operation in a different transaction. C. No data is affected until all locks are released. D. No data is affected until the transaction is in its locked position. Question 17 of 30 A (n) specifically reserves access to the transaction that locked the object. A. Exclusive lock B. Binary lock C. deadlock D. Shared lock Question 18 of 30 In the optimistic approach, during the phase, a transaction scans the database, executes the needed computations, and makes the updates to a private copy of the database values. A. Write B. Read C. Shared D. Validation Question 19 of 30 The information stored in the is used by the DBMS for a recovery requirement triggered by a ROLLBACK statement, a program’s abnormal termination, or a system failure such as a network discrepancy or a disk crash. A. Data dictionary B. Metadata C. Rollback Manager D. Transaction log Question 20 of 30 A consistent database is . A. one in which all data integrity constraints are satisfied, see page 622 B. one in which all tables are normalized C. one in which all tables have foreign keys INF3703-17-S1-1E Self Assessments D. one in which all SQL statements only update one table at a time Question 21 of 30 The manager is responsible for assigning and policing the locks used by the transactions. A. Lock B. Transaction C. Schedule D. Database Question 22 of 30 means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed. A. Serialisation B. Atomicity C. Isolation D. Consistency Question 23 of 30 A transaction is a unit of work that must be either entirely completed or aborted. A. Practical B. Timed C. Physical D. Logical Question 24 of 30 A lock prevents the use of any tables in the database from one transaction while another transaction is being processed. A. Database-level B. Table-level C. Page-level D. Row-level Question 25 of 30 requires that all operations of a transaction be completed. A. Time stamping B. Atomicity C. Specificity D. Durability Question 26 of 30 are required to prevent another transaction from reading inconsistent data. A. Locks B. Logs INF3703-17-S1-1E Self Assessments C. Stamps D. Schedules Question 27 of 30 A(n) phase in a two-phase lock is when a transaction releases all locks and cannot obtain any new lock. A. Growing B. Locking C. Shringing D. Unlocking Question 28 of 30 One of the three most common data integrity and consistency problems is . A. lost updates B. user errors C. disk failure D. deadlocks Question 29 of 30 The implicit beginning of a transaction is . A. when a table is accessed for the first time B. when a table is accessed for the first time C. when the COMMIT command is issued D. when the first SQL statement is encountered, see page 622 Question 30 of 30 As long as two transactions, T1 and T2, access data, there is no conflict, and the order of execution is irrelevant to the final outcome. A. Unrelated B. Common C. Locked D. Shared Chapter 13 Assessment