The following hints may help you stay energized, or at least ___________ until you can make the time for rest.

You plan to execute the following command to perform a Flashback Database operation in your database:
SQL> FLASHBACK DATABASE TO TIMESTAMP (SYSDATE -5/24);
Which two statements are true about this?（）

You use Microsoft .NET Framework 4 to create a Windows Presentation Foundation (WPF) application. 
You add a custom command as a resource. The key of the command is saveCommand. 
You write the following code fragment. (Line numbers are included for reference only.) 

You need to ensure that saveCommand is executed when the user clicks the Button control.
What should you do? （）

You executed the following commands in a database session:

What could have caused the recycle bin to clean up?（）

Before a Flashback Table operation, you execute the following command:
ALTER TABLE employees ENABLE ROW MOVEMENT;
Why would you need this to be executed?（）

You opened the encryption wallet and then issued the following command:

Then you closed the wallet. Later, you issued the following command to create the EMPLOYEES table in the SECURESPACE tablespace and you use the NO SALT option for the EMPID column.
What is the outcome?（）

Examine the parameter for your database instance:
You generated the execution plan for the following query in the plan table and noticed that the nested loop join was done. After actual execution of the query, you notice that the hash join was done in the execution plan:
Identify the reason why the optimizer chose different execution plans.（）

You executed the following command to drop a user:
DROP USER scott CASCADE;
Which two statements regarding the above command are correct?（）

You executed the following command to drop a user：  
DROP USER scott CASCADE；  
Which two statements regarding the above command are correct？（）

You executed the following SQL statement to shrink the EMPLOYEES table segment stored in the EXAMPLE tablespace:
ALTER TABLE employees SHRINK SPACE CASCADE;
Which statement is correct in this scenario?（）

You discover that your Recycle Bin contains two tables with the same name, MY_TABLE. You also have a table named MY_TABLE in your schema.You execute the following statement:
FLASHBACK TABLE my_table TO BEFORE DROP RENAME TO my_table2;
What will be the result of executing this statement?（）

You are working in an online transaction processing (OLTP) environment. You use the FLASHBACKTABLE command to flash back the CUSTOMERS table. Before executing the FLASHBACK TABLE command, the system change number (SCN) was 663571. After flashing back the CUSTOMERS table, you realize that the table is not in the correct state. Now, you need to reverse the effects of the FLASHBACK TABLE command.
Which is the fastest and the most efficient option to reverse the effects of the FLASHBACK TABLE command?（）