专业技术初级资格程序员基础知识DB2

试卷预览

• 21Which isolation level offers the greatest protection of data but provides the least amount of concurrency、

  A.Read Stability (RS)

  B.Cursor Stability (CS)

  C.Repeatable Read (RR)

  D.Uncommitted Read (UR)

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• 22What factor influences lock escalation、

  A.Table size

  B.Buffer space

  C.Number of locks

  D.Available real storage

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• 23Which type of lock allows the lock owner and all concurrent applications to read, but not update, the locked data、

  A.Share (S)

  B.Update (U)

  C.Exclusive (X)

  D.Intent Exclusive (IX)

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• 24Application APP_A is performing updates to table TAB1 using the cursor stability (CS) isolation level. If application APP_B wants to retrieve all rows from table TAB1 without waiting for application APP_A to finish making updates, what isolation level must application APP_B use、

  A.Read Stability (RS)

  B.Repeatable Read (RR)

  C.Uncommitted Read (UR)

  D.Cursor Stability (CS)

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• 25Which statement will prevent concurrent application processes from performing anything other than read-only operations against a table named TAB1、

  A.LOCK TABLE tab1 IN READ MODE

  B.LOCK TABLE tab1 IN SHARE MODE

  C.LOCK TABLE tab1 IN EXCLUSIVE MODE

  D.LOCK TABLE tab1 IN READ-ONLY MODE

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• 26When is an INTENT EXCLUSIVE (IX) lock required、

  A.When a transaction intends to read or change data.

  B.When a transaction intends to change but not read data.

  C.When a transaction intends to read but not change data.

  D.When a transaction intends to change the system catalog.

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• 27What is the act of exchanging one lock an application holds on a resource for a more restrictive lock on the same resource known as、

  A.Lock escalation

  B.Lock substitution

  C.Lock switch/exchange

  D.Lock conversion/promotion

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• 28What isolation level prevents dirty reads, nonrepeatable reads, and phantoms、

  A.Read stability (RS)

  B.Cursor stability (CS)

  C.Repeatable read (RR)

  D.Uncommitted read (UR)

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• 29Which operation normally does NOT require an exclusive lock、

  A.BIND

  B.DROP

  C.GRANT

  D.SELECT

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• 30When a COMMIT statement is executed, what happens、

  A.All locks held on the database are automatically released.

  B.Data stored in global temporary tables is automatically deleted.

  C.Open cursors defined WITH HOLD are closed, but their data is retaine

  D.D. The current transaction is terminated and a new transaction boundary is started.

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