SQL数据库操作练习：学生选课信息管理

(1) 建表语句：

CREATE TABLE SC( Sno CHAR(10) NOT NULL, Cno CHAR(10) NOT NULL, Grade FLOAT NOT NULL, PRIMARY KEY (Sno, Cno), FOREIGN KEY (Sno) REFERENCES Student(Sno), FOREIGN KEY (Cno) REFERENCES Course(Cno), CHECK (Grade >= 0 AND Grade <= 100) );

(2) 查询语句：

SELECT Sno, Sname FROM Student WHERE Sdept = '计算机系' AND Sage > 19;

(3) 更新语句：

UPDATE SC SET Grade = Grade + 10 WHERE Sno IN ( SELECT Sno FROM Student WHERE Ssex = '女' );

(4) 视图创建语句：

CREATE VIEW E_W AS SELECT SC.Sno, Student.Sname, SC.Cno, SC.Grade FROM SC INNER JOIN Student ON SC.Sno = Student.Sno WHERE Student.Sdept = '计算机系';