MySQL Errno 150

Question

I'm creating a few simple tables and I can't get passed this foreign key error and I'm not sure why. Here's the script below.

create TABLE Instructors (

ID varchar(10),
First_Name varchar(50) NOT NULL,
Last_Name varchar(50) NOT NULL,
PRIMARY KEY (ID)
);

create table Courses (

Course_Code varchar(10),
Title varchar(50) NOT NULL,
PRIMARY KEY (Course_Code)

);


create table Sections (
Index_No int,
Course_Code varchar(10),
Instructor_ID varchar(10),
PRIMARY KEY (Index_No),
FOREIGN KEY (Course_Code) REFERENCES Courses(Course_Code)
    ON DELETE cascade
    ON UPDATE cascade,
FOREIGN KEY (Instructor_ID) REFERENCES Instructors(ID)
    ON DELETE set default

);

Error Code: 1005. Can't create table '336_project.sections' (errno: 150)

My data types seem identical and the syntax seems correct. Can anyone point out what I'm not seeing here?

I'm using MySQL Workbench 5.2

Answer 1

This error also occurs if you are relating columns of different types, eg. int in the source table and BigInt in the destination table.