多项选择题
Which two statements describe good practices for an application developer to reduce lockingconflicts in Oracle database（）
A.Avoid coding unnecessary long-running transactions.
B.Allow the database to handle locks in default locking mode.
C.Always explicitly code the locks as per the requirement of the application.
D.Allow escalation of row locks to block locks if too many row locks cause problem.
相关考题
-
单项选择题
User A executes the following command to drop a large table in your database： SQL> DROP TABLE trans； While the drop table operation is in progress， user B executes the following command on the same table： SQL> DELETE FROM trans WHERE tr_type=’SL’； Which statement is true regarding the DELETE command（）
A.It fails with a "Resource Busy" error.
B.It deletes the rows successfully because the table is locked in SHARE mode.
C.It fails to delete the records because the table is locked in EXCLUSIVE mode.
D.It deletes the rows successfully because the table is locked in SHARE ROW EXCLUSIVE mode. -
单项选择题
You suspect unauthorized data manipulation language （DML） operations on a particular table. Youwant to track users who are performing the transactions and the values used in the transactions. You alsoplan to transfer these values to another table for analysis. How would you achieve this（）
A.by using triggers
B.by using Data Pump
C.by using external tables
D.by using anonymous PL/SQL blocks -
多项选择题
User SCOTT executes the following command on the EMP table but has not issued COMMIT， ROLLBACK， or any data definition language （DDL） command： SQL> SELECT ename FROM emp 2 WHERE job=’CLERK’ FOR UPDATE OF empno； SCOTT has opened another session to work with the database instance. Which three operations wouldwait when issued in SCOTT’s second session（）
A.LOCK TABLE emp IN SHARE MODE；
B.LOCK TABLE emp IN EXCLUSIVE MODE；
C.UPDATE emp SET sal=sal*1.2 WHERE job=MANAGER；
D.INSERT INTO emp（empno，ename） VALUES （1289，’Harry’）；
E.SELECT ename FROM emp WHERE job=’CLERK’ FOR UPDATE OF empno；
