CREATE TABLE student( sid INTEGER,
		      sname TEXT,
		      sex CHAR(1),
		      age INTEGER,
		      year INTEGER,
		      gpa NUMERIC,
		      PRIMARY KEY(sid)
		     );

CREATE TABLE dept( dname TEXT,
		   numphds INTEGER,
		   PRIMARY KEY(dname));

CREATE TABLE prof( dname TEXT,
		   pname TEXT,
		   PRIMARY KEY(pname),
		   FOREIGN KEY(dname) REFERENCES dept(dname) ON DELETE CASCADE);

CREATE TABLE course(cno INTEGER,
		   dname TEXT,
		   cname TEXT,
		   PRIMARY KEY(cno,dname),
		   FOREIGN KEY(dname) REFERENCES dept(dname) ON DELETE CASCADE );

CREATE TABLE major(dname TEXT,
		   sid INTEGER,
		   PRIMARY KEY(dname,sid),
		   FOREIGN KEY(dname) REFERENCES dept(dname) ON DELETE CASCADE,
		   FOREIGN KEY(sid) REFERENCES student(sid) ON DELETE CASCADE);

CREATE TABLE sections(dname TEXT,
		      cno INTEGER,
		      sectno INTEGER,
		      pname TEXT,
		      PRIMARY KEY(dname,cno,sectno),
		      FOREIGN KEY(cno,dname) REFERENCES course(cno,dname) ON DELETE CASCADE,
		      FOREIGN KEY (pname) REFERENCES prof(pname) ON DELETE CASCADE);

CREATE TABLE enroll(sid INTEGER,
		    grade NUMERIC,
		    dname TEXT,
		    cno INTEGER,
		    sectno INTEGER,
		    PRIMARY KEY(sid,dname,cno,sectno),
		    FOREIGN KEY(sid) REFERENCES student(sid) ON DELETE CASCADE,
		    FOREIGN KEY(cno,dname,sectno) REFERENCES sections(cno,dname,sectno) ON DELETE CASCADE);