Exercise Consider the following relational database: STUDENT (STDNO, SNAME, DEPTNO#) DEP (DEPTNO, DNAME) COURSE (CORSNO, CNAME, DEPTNO#, CMAX) ENROLMENT (STDNO#, CORSNO#, GRADE, EDATE) STUDENT.DEPTNO is the department number of the student. COURSE.DEPTNO is the department number that offers the course. ENROLMENT models the registrations of students in courses (M:M relationship) where the GRADE is the grade obtained by the student in the course. PARTI: DATA DESCRIPTION LANGUAGE (DDL) 1) Write DDL commands to create the four tables without any constraint. Nom de Signification Type Size colonne STDNO Student Number 8 Number SNAME Student Varchar2 30 name DEPTNO Department Varchar2 2 Number DNAME Department Varchar2 20 name CORSNO Course Number 3 Number CNAME Course Name Varchar2 30 CMAX Max. Number 2 students allowed GRADE Obtained Number 2 Grade EDATE Enrolment Date date 2) Add all the following constraints: - Primary Key - Foreign Key - Constraints on the STUDENT table: - Sname: Not Null - Each student must belong to a department