多项选择题
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.
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（）
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（）
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（）