Write a PL/SQL program to print reverse of a number. For example: 1234 print as 4321.

Create a trigger which will work before deletion in employee table and create a duplicate copy of the record in another table employee_backup.

Create a package which contains a procedure to accept a text and to check whether it is palindrome or not.

Create a package with procedure that shows the usage of the WHILE loop to calculate the average of user entered numbers and entry of more numbers are stopped by entering number 0?