Question

Here’s my script:

create table Country
(
CountryId int primary key,
Name varchar(255)
);

create table Person
(
PersonId int primary key,
Name varchar(255),
FOREIGN KEY (CountryId) references Country(CountryId)
);

I’m transitioning from MS SQL and trying to get a grasp on MySQL and starting off with my typical hello world of Person->Country relationship to get a feel for foreign keys.

I’m getting this error on PHPMyAdmin:

SQL query:

CREATE TABLE Person(

PersonId INT PRIMARY KEY , Name VARCHAR( 255 ) , FOREIGN KEY (
CountryId ) REFERENCES Country( CountryId ) );

MySQL said:

1072 – Key column ‘CountryId’ doesn’t exist in table

What newbie mistake am I making here?

Answer 1

That’s because you had not created the column in Person that would be used in the foreign key, thus, Key column 'CountryId' doesn't exist in table. Here’s how you’d do it:

CREATE TABLE Person(
    PersonId INT PRIMARY KEY , 
    Name VARCHAR( 255 ) , 
    CountryId int,
    FOREIGN KEY ( CountryId ) REFERENCES Country( CountryId )
);