Question 1
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1. Most real-world database transactions are formed by only one database request.
Question 2
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2. Although the DBMS is designed to recover a database to a previous consistent state when an interruption prevents the completion of a required set of transactions, the transactions themselves are defined by the end user or programmer and must be semantically correct.
Question 3
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3. The DBMS guarantees that the semantic meaning of a transaction truly represents the real-world event.
Question 4
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4. Atomicity indicates the permanence of the database's consistent state.
Question 5
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5. Serializability means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.
Question 6
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6. Incomplete or improper transactions can have a devastating effect on database integrity.
Question 7
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7. 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.
Question 8
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8. The multiuser DBMS must implement controls to ensure serializability and isolation of transactions, in addition to atomicity and durability, in order to guard the database's consistency and integrity.
Question 9
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9. 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.
Question 10
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10. The scheduler establishes the order in which the operations within concurrent transactions are executed.
Question 11
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11. A scheduler facilitates data isolation to ensure that two transactions do not update the same data element at the same time.
Question 12
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12. A lock guarantees the open use of a data item to multiple transactions.
Question 13
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13. In a page-level lock, the DBMS will lock an entire diskpage.
Question 14
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14. A field-level lock allows concurrent transactions to access the same row, as long as they require the use of different fields within that row.
Question 15
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15. A shared lock produces no conflict as long as all the concurrent transactions are read-write only.
Question 16
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16. A growing phase in a two-phase lock is when a transaction acquires all the required locks without locking any data.
Question 17
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17. Timestamps must only have the single property of uniqueness.
Question 18
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18. Time stamping demands a lot of system resources because many transactions might have to be stopped, rescheduled, and stamped.
Question 19
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19. An optimistic approach is based on the assumption that the majority of the database operations do not conflict.
Question 20
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20. When using an optimistic approach, during the read phase, a transaction reads the database, executes the needed computations, and makes the updates to a private copy of the database values.
Question 21
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21. The serializable isolation level is the least restrictive level defined by the ANSI SQL standard.
Question 22
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22. The reason for the different levels of isolation is to increase transaction concurrency.
Question 23
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23. The transaction recovery write-ahead-log protocol ensures that transaction logs are always written before any database data are actually updated.
Question 24
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24. The last step in the write-through technique recovery procedure is to identify the last checkpoint in the transaction log.
Question 25
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25. A transaction is a unit of work that must be either entirely completed or aborted.
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a. timed
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b. practical
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c. logical
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d. physical
Question 26
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26. A consistent database state is .
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a. one in which all tables have foreign keys
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b. one in which all data integrity constraints are satisfied
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c. one in which all tables are normalized
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d. one in which all SQL statements only update one table at a time
Question 27
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27. requires that all operations of a transaction be completed.
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a. Specificity
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b. Atomicity
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c. Durability
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d. Time stamping
Question 28
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28. means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.
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a. Serializability
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b. Atomicity
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c. Isolation
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d. Time stamping
Question 29
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29. A single-user database system automatically ensures of the database, because only one transaction is executed at a time.
Answer
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a. serializability and durability
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b. atomicity and isolation
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c. serializability and isolation
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d. atomicity and serializability
Question 30
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30. The ANSI has defined standards that govern SQL database transactions. Transaction support is provided by two SQL statements: and ROLLBACK
Answer
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a. RETRIEVE
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b. ASSIGN
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c. UPDATE
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d. COMMIT
Question 31
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31. ANSI defines four events that signal the end of a transaction. Of the following events, which is defined by ANSI as being equivalent to a COMMIT?
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a. Five SQL statements are executed.
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b. The end of a program is successfully reached.
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c. The program is abnormally terminated.
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d. The database is shut down for maintenance.
Question 32
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32. ANSI defines four events that signal the end of a transaction. Of the following events, which is defined by ANSI as being equivalent to a ROLLBACK?
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a. Five SQL statements are executed.
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b. The end of a program is successfully reached.
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c. The program is abnormally terminated.
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d. The database is shut down for maintenance.
Question 33
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33. The implicit beginning of a transaction is .
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a. when the database is started
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b. when a table is accessed for the first time
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c. when the first SQL statement is encountered
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d. when the COMMIT command is issued
Question 34
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34. 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.
Answer
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a. data dictionary
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b. metadata
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c. rollback manager
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d. transaction log
Question 35
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35. One of the three most common data integrity and consistency problems is .
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a. lost updates
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b. disk failures
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c. user errors
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d. deadlocks
Question 36
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36. occurs when a transaction accesses data before and after one or more other transactions finish working with such data.
Question 37
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37. 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.
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a. shared
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b. common
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c. unrelated
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d. locked
Question 38
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38. are required to prevent another transaction from reading inconsistent data.
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a. Locks
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b. Schedules
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c. Stamps
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d. Logs
Question 39
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39. The______ manager is responsible for assigning and policing the locks used by the transactions.
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a. transaction
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b. database
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c. lock
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d. schedule
Question 40
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40. Lock indicates the level of lock use.
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a. granularity
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b. shrinking
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c. growing
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d. serializability
Question 41
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41. A lock locks the entire table preventing access to any row by a transaction while another transaction is using the table.
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a. database-level
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b. table-level
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c. page-level
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d. row-level
Question 42
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42. A lock locks the entire diskpage.
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a. transaction-level
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b. table-level
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c. page-level
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d. row-level
Question 43
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43. A diskpage, or page, is the equivalent of a .
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a. database table
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b. disk sector
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c. database schema
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d. diskblock
Question 44
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44. A lock allows concurrent transactions to access different rows of the same table.
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a. database-level
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b. table-level
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c. page-level
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d. row-level
Question 45
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45. A(n) specifically reserves access to the transaction that locked the object.
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a. shared lock
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b. exclusive lock
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c. binary lock
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d. deadlock
Question 46
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46. A(n) lock exists when concurrent transactions are granted read access on the basis of a common lock
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a. shared
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b. exclusive
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c. binary
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d. two-phase
Question 47
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47. What is a rule that applies to the two-phase locking protocol?
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a. Two transactions cannot have conflicting locks.
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b. No unlock operation can precede a lock operation in a different transaction
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c. No data is affected until all locks are released.
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d. No data is affected until the transaction is in its locked position
Question 48
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48. A(n) phase in a two-phase lock is when a transaction releases all locks and cannot obtain any new lock.
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a. growing
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b. shrinking
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c. locking
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d. unlocking
Question 49
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49. A(n) condition occurs when two or more transactions wait for each other to unlock data.
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a. deadlock
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b. exclusive lock
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c. binary lock
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d. two-phase lock
Question 50
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50. The approach to scheduling concurrent transactions assigns a global unique stamp to each transaction.
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a. scheduled
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b. table-locking
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c. unique
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d. timestamping
Question 51
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51. In the wait/die scheme,:
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a. the older transaction rolls back the younger transaction and reschedules it.
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b. the younger, preempted transaction is rescheduled using the same time stamp.
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c. the older transaction waits for the younger one to complete and release its locks.
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d. both the younger and older transactions wait indefinitely to be released.
Question 52
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52. 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.
Answer
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a. read
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b. validation
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c. write
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d. shared
Question 53
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53. In the optimistic approach, during the phase, changes are permanently applied to the database.
Answer
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a. read
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b. validation
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c. write
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d. shared
Question 54
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54. The isolation level ensures that queries return consistent results.
Answer
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a. Read Uncommitted
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b. Read Committed
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c. Serializable
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d. Repeatable Read
Question 55
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55. A(n) occurs when a transaction executes a query at time t1, and then it runs the same query at time t2, yielding additional rows that satisfy the query.