示例关系 DEPTONO, DNAME, DEAN S(Sno, SNAME, SEX, AGE, D# COURSE(CnO, CN, PCno, CREDIT SC(Sno, Cno, SCORE) PROF(Pno, PNAME, AGE, D#, SAL) Teach(Pno, Cno)示例关系 DEPT(DNO , DNAME , DEAN) S(Sno , SNAME , SEX , AGE , D#) COURSE(Cno , CN , PCno, CREDIT) SC(Sno , Cno , SCORE) PROF(Pno , PNAME, AGE, D# , SAL) Teach(Pno , Cno)