记录SQL作业

CREATE DATABASE educ CHARACTER SET utf8;

USE educ;

CREATE TABLE student(sno CHAR(7) PRIMARY KEY, 
                     sname CHAR(10) NOT NULL, 
                     sex CHAR(2), 
                     birthday DATE);

CREATE TABLE course(cno CHAR(2) PRIMARY KEY,
                   cname CHAR(20) NOT NULL UNIQUE,
                   credit SMALLINT,
                   ctime SMALLINT);

CREATE TABLE score(sno CHAR(7),
                  cno CHAR(2),
                  grade SMALLINT,
                  PRIMARY KEY(sno, cno),
                  FOREIGN KEY(sno) REFERENCES student(sno) ON DELETE CASCADE ON UPDATE CASCADE,
                  FOREIGN KEY(cno) REFERENCES course(cno) ON DELETE CASCADE ON UPDATE CASCADE);