Database Systems 6th Edition by Ramez Elmasri, Shamkant B. Navathe

Exercise 1

-Consider the COMPANY database described in Figure 3.6. Using the syntax of Oracle triggers, write active rules to do the following:
(a) Whenever an employee's project assignments are changed, check if the total hours per week spent on the employee's projects are less than 30 or greater than 40; if so, notify the employee's direct supervisor.
(b) Whenever an EMPLOYEE is deleted, delete the PROJECT tuples and DEPENDENT
tuples related to that employee, and if the employee is managing a department or supervising any employees, set the MGRSSN for that department to null and set the SUPERSSN for those employees to null.