MySQL : ERROR 1215 (HY000): Cannot add foreign key constraint

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误落风尘
误落风尘 2020-11-30 01:37

I have read Database system concepts, 6th edition, Silberschatz. I\'m going to implement the university database system shown in chapter 2 on OS X

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  •  失恋的感觉
    2020-11-30 02:20

    The syntax of FOREIGN KEY for CREATE TABLE is structured as follows:

    FOREIGN KEY (index_col_name)
            REFERENCES table_name (index_col_name,...)
    

    So your MySQL DDL should be:

     create table course (
            course_id varchar(7),
            title varchar(50),
            dept_name varchar(20),
            credits numeric(2 , 0 ),
            primary key (course_id),
            FOREIGN KEY (dept_name)
                REFERENCES department (dept_name)
        );
    

    Also, in the department table dept_name should be VARCHAR(20)

    More information can be found in the MySQL documentation

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