mysql相关

• 创建表

CREATE TABLE student(
    Sno CHAR(9) PRIMARY KEY,
    Sname CHAR(20) UNIQUE,
    Ssex CHAR(2),
    Sage SMALLINT,
    Sdept CHAR(20)
);
CREATE TABLE course(
    Cno CHAR(4) PRIMARY KEY,
    Cname CHAR(40) NOT NULL,
    Cpno CHAR(4),
    Ccredit SMALLINT,
    FOREIGN KEY (Cpno) REFERENCES course(Cno)
);

CREATE TABLE SC(
    Sno CHAR(9),
    Cno CHAR(4),
    Grade SMALLINT,
    PRIMARY KEY(Sno, Cno),
    FOREIGN KEY(Sno) REFERENCES student(Sno),
    FOREIGN KEY(Cno) REFERENCES course(Cno)
);

• 表中数据

 

•  具体操作