单选题Which of the following best describes the lock protection provided by DB2 for the current row of a cursor?（）A The cursor is only protected from updates and deletes by concurrent applications.B The row is only protected from positioned updates and delet

第1题：

Which of the following will help protect an operating system from vulnerability？（）

• A、Download free anti-virus programs from the Internet.
• B、Perform updates from the manufacturers website regularly.
• C、Using the operating systems email program only to open attachments.
• D、Monitoring what is displayed on the screen.

第2题：

Which of the following is TRUE for the DB2 isolation level Cursor Stability (CS)?（）

• A、An application process acquires at least a share lock on the current row of every cursor.
• B、Any row that is read during a unit of work cannot be changed by other application processes until the unit of work is complete.
• C、Any row changed by another application process can be read, even if the change has not been committed by that application process.
• D、An application process that issues the same query more than once in a unit of work will not see additional rows caused by other application processes appending new information to the database.

第3题：

A customer wants to have employees work from remote locations as well as in the office.  All communications must be secure and files must be protected from access by unauthorized people.  The employee’s applications （database inserts and reads） are only accessed with a web browser.  Which of the following capabilities is necessary？（）

• A、SSL
• B、PGP
• C、File encryption program
• D、Public key encryption

第4题：

Which two statements are correct regarding the Flashback Versions Query feature？（）

• A、 You can use this feature to identify the committed versions of the rows， but not the uncommitted versions.
• B、 You can use this feature to identify the versions of V$ views.
• C、 You can use this feature to identify the inserts， deletes， and updates performed on a particular row but not the data definition language （DDL） operations performed on the table.
• D、 You can use this feature for a table only if row movement is enabled for the table.
• E、 You can use this feature to identify the versions of external and fixed tables.

第5题：

Consider this syntax：   MERGE INTO t1  USING t2 ON （join predicate）…..   What does the MERGE syntax do？（）

• A、It performs a merge join of the row from T2 only if it doesn’t exist in the T1 table. 
• B、It creates a natural join of tables T1 and T2 for all columns that have the same name. 
• C、It creates a Cartesian product of table T1 and table T2 for all columns that have the same name. 
• D、For each row from T2, it updates the row if it exists within table T1, otherwise it inserts the row into T1.

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第13题：

The opening of cursor CSR01 produces the following result set: STUDENT LASTNM FIRSTNM CLASSNO 123 Brown John T100 213 Bailey James T100 312 Carter Arlene T210 465 Chas Devon T305 546 Davis Steven T405 If this Fetch statement is executed: FETCH csr01 INTO :studnum, :firstname, :lastname, :class Which of the following DELETE statements will cause this row to be deleted?（）

• A、DELETE ALL FROM tab01 FOR CURRENT OF csr01
• B、DELETE FROM tab01 FOR CURRENT csr01 WITH RS
• C、DELETE * FROM tab01 WHERE CURRENT csr01 WITH CS
• D、DELETE FROM tab01 WHERE CURRENT OF csr01 WITH RR

第14题：

Which of the following best describes the lock protection provided by DB2 for the current row of a cursor?（）

• A、The cursor is only protected from updates and deletes by concurrent applications.
• B、The row is only protected from positioned updates and deletes that reference another cursor of the same application.
• C、The cursor is protected from positioned updates and deletes that reference another cursor of a different application.
• D、The row is protected from updates and deletes by the current application and from positioned updates and deletes that reference another cursor of the same application.

第15题：

Which of the following best describes how locks are used in DB2?（）

• A、To maintain control of updated rows for commit processing
• B、To ensure only committed changes are altered by another application
• C、To allow two applications to update the same row of data simultaneously
• D、To prevent multiple applications from accessing the same data simultaneously

第16题：

Which two statements about subqueries are true?（）

• A、A single row subquery can retrieve data from only one table.
• B、A SQL query statement cannot display data from table B that is referred to in its subquery, unless table B is included in the main query's FROM clause.
• C、A SQL query statement can display data from table B that is referred to in its subquery, without including table B in its own FROM clause.
• D、A single row subquery can retrieve data from more than one table.
• E、A single row subquery cannot be used in a condition where the LIKE operator is used for comparison.
• F、A multiple-row subquery cannot be used in a condition where the LIKE operator is used for comparison.

第17题：

Which two statements are true regarding single row functions?（）

• A、They accept only a single argument 
• B、They can be nested only to two levels 
• C、Arguments can only be column values or constants 
• D、They always return a single result row for every row of a queried table 
• E、They can return a data type value different from the one that is referenced

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