MYSQL 外键错误

Question

我正在尝试使用 jdbc 创建一个简单的表，但它给了我一个错误。这是我的代码:

public class Test {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        Class.forName("com.mysql.jdbc.Driver");
        Connection con = DriverManager.getConnection("jdbc:mysql://localhost/javabook","scott","tiger");
        System.out.println("part 1:DONE !");
        Statement statement = con.createStatement();
        String query = "create table Enrollment (ssn char(9), courseId char(5), dateRegistered date, grade char(2)"+
                    "primary key (ssn, courseId), foreign key (ssn) references Student (ssn), foreign key (courseId) references Course(courseId)";

        statement.executeUpdate(query);
        System.out.println("part 2:DONE !");
    }
}

我收到此错误:

Exception in thread "main" com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:936)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2985)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1631)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
    at com.mysql.jdbc.Connection.execSQL(Connection.java:3277)
    at com.mysql.jdbc.Statement.executeUpdate(Statement.java:1402)
    at com.mysql.jdbc.Statement.executeUpdate(Statement.java:1317)
    at Test.main(Test.java:17)

Answer 1

您在代码中漏掉了右括号“)”。在代码中使用以下语句。

字符串查询=“创建表Enrollment(ssn char(9)，courseId char(5)，date注册日期，grade char(2)”+ “主键(ssn，courseId)，外键(ssn)引用Student(ssn)，外键(courseId)引用Course(courseId))”；

请确保右括号。