Exercise 3 (2 pts)

Write a CHECK constraint that expresses the following condition on table Schedule in University Database: In each term occurring in this table, at least two courses are offered. Hint: Use NOT EXISTS.

Schedule

CourseId	Term	InstrId
CS 200	Fall 2016	003
CS 200	Fall 2017	003
CS 300	Spring 2017	003
CS 400	Fall 2016	004
CS 400	Fall 2017	004
Math 200	Fall 2016	001
Math 200	Spring 2017	004
Math 200	Fall 2017	001
Phys 400	Spring 2017	002