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CHAPTER 10: TRANSACTION MANAGEMENT AND CONCURRENCY CONTROL

Beschreibung

CIS 3365 Quiz am CHAPTER 10: TRANSACTION MANAGEMENT AND CONCURRENCY CONTROL, erstellt von Miguel Lucero am 05/04/2017.
Miguel Lucero
Quiz von Miguel Lucero, aktualisiert more than 1 year ago
Miguel Lucero
Erstellt von Miguel Lucero vor mehr als 7 Jahre
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Zusammenfassung der Ressource

Frage 1

Frage
1. Most real-world database transactions are formed by only one database request.
Antworten
  • True
  • False

Frage 2

Frage
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.
Antworten
  • True
  • False

Frage 3

Frage
3. The DBMS guarantees that the semantic meaning of a transaction truly represents the real-world event.
Antworten
  • True
  • False

Frage 4

Frage
4. Atomicity indicates the permanence of the database's consistent state.
Antworten
  • True
  • False

Frage 5

Frage
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.
Antworten
  • True
  • False

Frage 6

Frage
6. Incomplete or improper transactions can have a devastating effect on database integrity.
Antworten
  • True
  • False

Frage 7

Frage
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.
Antworten
  • True
  • False

Frage 8

Frage
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.
Antworten
  • True
  • False

Frage 9

Frage
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.
Antworten
  • True
  • False

Frage 10

Frage
10. The scheduler establishes the order in which the operations within concurrent transactions are executed.
Antworten
  • True
  • False

Frage 11

Frage
11. A scheduler facilitates data isolation to ensure that two transactions do not update the same data element at the same time.
Antworten
  • True
  • False

Frage 12

Frage
12. A lock guarantees the open use of a data item to multiple transactions.
Antworten
  • True
  • False

Frage 13

Frage
13. In a page-level lock, the DBMS will lock an entire diskpage.
Antworten
  • True
  • False

Frage 14

Frage
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.
Antworten
  • True
  • False

Frage 15

Frage
15. A shared lock produces no conflict as long as all the concurrent transactions are read-write only.
Antworten
  • True
  • False

Frage 16

Frage
16. A growing phase in a two-phase lock is when a transaction acquires all the required locks without locking any data.
Antworten
  • True
  • False

Frage 17

Frage
17. Timestamps must only have the single property of uniqueness.
Antworten
  • True
  • False

Frage 18

Frage
18. Time stamping demands a lot of system resources because many transactions might have to be stopped, rescheduled, and stamped.
Antworten
  • True
  • False

Frage 19

Frage
19. An optimistic approach is based on the assumption that the majority of the database operations do not conflict.
Antworten
  • True
  • False

Frage 20

Frage
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.
Antworten
  • True
  • False

Frage 21

Frage
21. The serializable isolation level is the least restrictive level defined by the ANSI SQL standard.
Antworten
  • True
  • False

Frage 22

Frage
22. The reason for the different levels of isolation is to increase transaction concurrency.
Antworten
  • True
  • False

Frage 23

Frage
23. The transaction recovery write-ahead-log protocol ensures that transaction logs are always written before any database data are actually updated.
Antworten
  • True
  • False

Frage 24

Frage
24. The last step in the write-through technique recovery procedure is to identify the last checkpoint in the transaction log.
Antworten
  • True
  • False

Frage 25

Frage
25. A transaction is a unit of work that must be either entirely completed or aborted.
Antworten
  • a. timed
  • b. practical
  • c. logical
  • d. physical

Frage 26

Frage
26. A consistent database state is .
Antworten
  • a. one in which all tables have foreign keys
  • b. one in which all data integrity constraints are satisfied
  • c. one in which all tables are normalized
  • d. one in which all SQL statements only update one table at a time

Frage 27

Frage
27. requires that all operations of a transaction be completed.
Antworten
  • a. Specificity
  • b. Atomicity
  • c. Durability
  • d. Time stamping

Frage 28

Frage
28. means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.
Antworten
  • a. Serializability
  • b. Atomicity
  • c. Isolation
  • d. Time stamping

Frage 29

Frage
29. A single-user database system automatically ensures of the database, because only one transaction is executed at a time.
Antworten
  • a. serializability and durability
  • b. atomicity and isolation
  • c. serializability and isolation
  • d. atomicity and serializability

Frage 30

Frage
30. The ANSI has defined standards that govern SQL database transactions. Transaction support is provided by two SQL statements: and ROLLBACK
Antworten
  • a. RETRIEVE
  • b. ASSIGN
  • c. UPDATE
  • d. COMMIT

Frage 31

Frage
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?
Antworten
  • a. Five SQL statements are executed.
  • b. The end of a program is successfully reached.
  • c. The program is abnormally terminated.
  • d. The database is shut down for maintenance.

Frage 32

Frage
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?
Antworten
  • a. Five SQL statements are executed.
  • b. The end of a program is successfully reached.
  • c. The program is abnormally terminated.
  • d. The database is shut down for maintenance.

Frage 33

Frage
33. The implicit beginning of a transaction is .
Antworten
  • a. when the database is started
  • b. when a table is accessed for the first time
  • c. when the first SQL statement is encountered
  • d. when the COMMIT command is issued

Frage 34

Frage
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.
Antworten
  • a. data dictionary
  • b. metadata
  • c. rollback manager
  • d. transaction log

Frage 35

Frage
35. One of the three most common data integrity and consistency problems is .
Antworten
  • a. lost updates
  • b. disk failures
  • c. user errors
  • d. deadlocks

Frage 36

Frage
36. occurs when a transaction accesses data before and after one or more other transactions finish working with such data.
Antworten
  • a. Inconsistent retrievals
  • b. The phenomena of uncommitted data
  • c. Lost update problems
  • d. Dirty read problems

Frage 37

Frage
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.
Antworten
  • a. shared
  • b. common
  • c. unrelated
  • d. locked

Frage 38

Frage
38. are required to prevent another transaction from reading inconsistent data.
Antworten
  • a. Locks
  • b. Schedules
  • c. Stamps
  • d. Logs

Frage 39

Frage
39. The______ manager is responsible for assigning and policing the locks used by the transactions.
Antworten
  • a. transaction
  • b. database
  • c. lock
  • d. schedule

Frage 40

Frage
40. Lock indicates the level of lock use.
Antworten
  • a. granularity
  • b. shrinking
  • c. growing
  • d. serializability

Frage 41

Frage
41. A lock locks the entire table preventing access to any row by a transaction while another transaction is using the table.
Antworten
  • a. database-level
  • b. table-level
  • c. page-level
  • d. row-level

Frage 42

Frage
42. A lock locks the entire diskpage.
Antworten
  • a. transaction-level
  • b. table-level
  • c. page-level
  • d. row-level

Frage 43

Frage
43. A diskpage, or page, is the equivalent of a .
Antworten
  • a. database table
  • b. disk sector
  • c. database schema
  • d. diskblock

Frage 44

Frage
44. A lock allows concurrent transactions to access different rows of the same table.
Antworten
  • a. database-level
  • b. table-level
  • c. page-level
  • d. row-level

Frage 45

Frage
45. A(n) specifically reserves access to the transaction that locked the object.
Antworten
  • a. shared lock
  • b. exclusive lock
  • c. binary lock
  • d. deadlock

Frage 46

Frage
46. A(n) lock exists when concurrent transactions are granted read access on the basis of a common lock
Antworten
  • a. shared
  • b. exclusive
  • c. binary
  • d. two-phase

Frage 47

Frage
47. What is a rule that applies to the two-phase locking protocol?
Antworten
  • 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

Frage 48

Frage
48. A(n) phase in a two-phase lock is when a transaction releases all locks and cannot obtain any new lock.
Antworten
  • a. growing
  • b. shrinking
  • c. locking
  • d. unlocking

Frage 49

Frage
49. A(n) condition occurs when two or more transactions wait for each other to unlock data.
Antworten
  • a. deadlock
  • b. exclusive lock
  • c. binary lock
  • d. two-phase lock

Frage 50

Frage
50. The approach to scheduling concurrent transactions assigns a global unique stamp to each transaction.
Antworten
  • a. scheduled
  • b. table-locking
  • c. unique
  • d. timestamping

Frage 51

Frage
51. In the wait/die scheme,:
Antworten
  • a. the older transaction rolls back the younger transaction and reschedules it.
  • b. the younger, preempted transaction is rescheduled using the same time stamp.
  • c. the older transaction waits for the younger one to complete and release its locks.
  • d. both the younger and older transactions wait indefinitely to be released.

Frage 52

Frage
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.
Antworten
  • a. read
  • b. validation
  • c. write
  • d. shared

Frage 53

Frage
53. In the optimistic approach, during the phase, changes are permanently applied to the database.
Antworten
  • a. read
  • b. validation
  • c. write
  • d. shared

Frage 54

Frage
54. The isolation level ensures that queries return consistent results.
Antworten
  • a. Read Uncommitted
  • b. Read Committed
  • c. Serializable
  • d. Repeatable Read

Frage 55

Frage
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.
Antworten
  • a. phantom read
  • b. dirty read
  • c. uncommitted dependency
  • d. nonrepeatable read
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