(a) Use the Structured Query Language to create enroll table with proper primary key, foreign key, and according to the following constraints. Assumptions: the student table and course table have been already created for the database. (1) student# must be defined as an integer and existed in the student table; (2) course# must be defined as a small integer and a value in the course table; (3) semesterdate has a default value of fall 2015; (4) grade has to be equal to a value of A, or B, or C, or D, or F or W; (5) a student cannot enroll in the same class twice and/or more than 5 classes in the same semester; and (6) any course can only have up to 50 students enrolled in the course.