1Z0-042單項(xiàng)選擇題每日一練(2019.01.19)

You work as a database administrator for Certkiller .com. You received the following error while working on your database：
ORA-01555： snapshot too old 
In which situation would you receive such an error？（）

Exhibit：
View the Exhibit to see the information on existing tablespaces of the PROD database. 
You observe that a large volume of INSERTs and DELETEs are happening on the TRANS table residing in the USERS tablespace， and you suspect that the TRANS table is fragmented. Which advisory component would you refer to， in order to find the information about table fragmentation？（）

You execute the following command to audit the database activities： 
SQL> AUDIT DROP ANY TABLE BY scott BY SESSION WHENEVER SUCCESSFUL； 
What is the effect of this command？（）