create table Student115( sno char(7) primary key comment '学号', sname varchar(10) not null, ssex char(2) check(gender in('男','女')), sage int check(sage>=15 and sage<=45), sdept varchar(20) DEFAULT '计算机系' ); create table course115( cno char(10) primary key, cname varchar(20) not null, credit int check(credit>0), semester int check(credit>0), period int not null ); create table sc115( sno char(7), cno varchar(10), grade int check(grade>=0 and grade<=100), primary key (student115,course115,sc1115), foreign key(sno) references Student115(sno), foreign key(cno) references course115(cno) );为什么无法运行

可能是因为在创建 sc115 表时，主键的命名有误，应该是 primary key (sno,cno)，而不是 primary key (student115,course115,sc1115)。此外，semester 字段的约束条件应该是 semester>=1 and semester<=2，而不是 credit>。

相关问题

create database Schhool115; use schhool115; create table Student115( sno char(7) primary key comment '学号', sname varchar(10) not null, ssex char(2) check(gender in('男','女')), sage int check(sage>=15 and sage<=45), sdept varchar(20) DEFAULT '计算机系' ); crea

te database Schhool115; use schhool115; create table Student115( sno char(7) primary key comment '学号', sname varchar(10) not null, ssex char(2) check(gender in('男','女')), sage int check(sage>=15 and sage<=45), sdept varchar(20) DEFAULT '计算机系' );

这是一个 SQL 数据库的创建语句，用于创建一个名为 Schhool115 的数据库，并在其中创建一个名为 Student115 的表格，包含学号、姓名、性别、年龄和所在系别等字段。

将以下代码给为mysql代码：create table student(sno char(5) primary key, sname varchar(20), sage int, ssex char(2), sdept char(15)); create table course(cno char(3) primary key, cname varchar(20), cpno char(3), ccredit int, foreign key(cpno) references course); create table sc( sno char(5), cno char(3), grade int, primary key(sno,cno), foreign key(sno) references student, foreign key(cno) references course, check(grade>=0 and grade<=100));

以下是对应的 MySQL 代码：

-- Connect to the database
mysql -h hostname -u username -p password

-- Create the student table
CREATE TABLE student (
    sno CHAR(5) PRIMARY KEY,
    sname VARCHAR(20),
    sage INT,
    ssex CHAR(2),
    sdept CHAR(15)
);

-- Create the course table
CREATE TABLE course (
    cno CHAR(3) PRIMARY KEY,
    cname VARCHAR(20),
    cpno CHAR(3),
    ccredit INT,
    FOREIGN KEY (cpno) REFERENCES course (cno)
);

-- Create the sc table
CREATE TABLE sc (
    sno CHAR(5),
    cno CHAR(3),
    grade INT,
    PRIMARY KEY (sno, cno),
    FOREIGN KEY (sno) REFERENCES student (sno),
    FOREIGN KEY (cno) REFERENCES course (cno),
    CHECK (grade >= 0 AND grade <= 100)
);

-- Close the connection
QUIT;

需要注意的是，在 MySQL 中，`CHECK` 约束不能使用函数，只能使用常量表达式。因此，`CHECK(grade >= 0 AND grade <= 100)` 不能写成 `CHECK(BETWEEN grade AND 0 AND 100)`。