I was working on creating some tables in database foo, but every time I end up with errno 150 regarding the foreign key. Firstly, here's my code for creating tables:
CREATE TABLE Clients
(
client_id CHAR(10) NOT NULL ,
client_name CHAR(50) NOT NULL ,
provisional_license_num CHAR(50) NOT NULL ,
client_address CHAR(50) NULL ,
client_city CHAR(50) NULL ,
client_county CHAR(50) NULL ,
client_zip CHAR(10) NULL ,
client_phone INT NULL ,
client_email CHAR(255) NULL ,
client_dob DATETIME NULL ,
test_attempts INT NULL
);
CREATE TABLE Applications
(
application_id CHAR(10) NOT NULL ,
office_id INT NOT NULL ,
client_id CHAR(10) NOT NULL ,
instructor_id CHAR(10) NOT NULL ,
car_id CHAR(10) NOT NULL ,
application_date DATETIME NULL
);
CREATE TABLE Instructors
(
instructor_id CHAR(10) NOT NULL ,
office_id INT NOT NULL ,
instructor_name CHAR(50) NOT NULL ,
instructor_address CHAR(50) NULL ,
instructor_city CHAR(50) NULL ,
instructor_county CHAR(50) NULL ,
instructor_zip CHAR(10) NULL ,
instructor_phone INT NULL ,
instructor_email CHAR(255) NULL ,
instructor_dob DATETIME NULL ,
lessons_given INT NULL
);
CREATE TABLE Cars
(
car_id CHAR(10) NOT NULL ,
office_id INT NOT NULL ,
engine_serial_num CHAR(10) NULL ,
registration_num CHAR(10) NULL ,
car_make CHAR(50) NULL ,
car_model CHAR(50) NULL
);
CREATE TABLE Offices
(
office_id INT NOT NULL ,
office_address CHAR(50) NULL ,
office_city CHAR(50) NULL ,
office_County CHAR(50) NULL ,
office_zip CHAR(10) NULL ,
office_phone INT NULL ,
office_email CHAR(255) NULL
);
CREATE TABLE Lessons
(
lesson_num INT NOT NULL ,
client_id CHAR(10) NOT NULL ,
date DATETIME NOT NULL ,
time DATETIME NOT NULL ,
milegage_used DECIMAL(5, 2) NULL ,
progress CHAR(50) NULL
);
CREATE TABLE DrivingTests
(
test_num INT NOT NULL ,
client_id CHAR(10) NOT NULL ,
test_date DATETIME NOT NULL ,
seat_num INT NOT NULL ,
score INT NULL ,
test_notes CHAR(255) NULL
);
ALTER TABLE Clients ADD PRIMARY KEY (client_id);
ALTER TABLE Applications ADD PRIMARY KEY (application_id);
ALTER TABLE Instructors ADD PRIMARY KEY (instructor_id);
ALTER TABLE Offices ADD PRIMARY KEY (office_id);
ALTER TABLE Lessons ADD PRIMARY KEY (lesson_num);
ALTER TABLE DrivingTests ADD PRIMARY KEY (test_num);
ALTER TABLE Applications ADD CONSTRAINT FK_Applications_Offices FOREIGN KEY (office_id) REFERENCES Offices (office_id);
ALTER TABLE Applications ADD CONSTRAINT FK_Applications_Clients FOREIGN KEY (client_id) REFERENCES Clients (client_id);
ALTER TABLE Applications ADD CONSTRAINT FK_Applications_Instructors FOREIGN KEY (instructor_id) REFERENCES Instructors (instructor_id);
ALTER TABLE Applications ADD CONSTRAINT FK_Applications_Cars FOREIGN KEY (car_id) REFERENCES Cars (car_id);
ALTER TABLE Lessons ADD CONSTRAINT FK_Lessons_Clients FOREIGN KEY (client_id) REFERENCES Clients (client_id);
ALTER TABLE Cars ADD CONSTRAINT FK_Cars_Offices FOREIGN KEY (office_id) REFERENCES Offices (office_id);
ALTER TABLE Clients ADD CONSTRAINT FK_DrivingTests_Clients FOREIGN KEY (client_id) REFERENCES Clients (client_id);
These are the errors that I get:
mysql> ALTER TABLE Applications ADD CONSTRAINT FK_Applications_Cars FOREIGN KEY
(car_id) REFERENCES Cars (car_id);
ERROR 1005 (HY000): Can't create table 'foo.#sql-12c_4' (errno: 150)
I ran SHOW ENGINE INNODB STATUS which gives a more detailed error description:
------------------------
LATEST FOREIGN KEY ERROR
------------------------
100509 20:59:49 Error in foreign key constraint of table foo/#sql-12c_4:
FOREIGN KEY (car_id) REFERENCES Cars (car_id):
Cannot find an index in the referenced table where the
referenced columns appear as the first columns, or column types
in the table and the referenced table do not match for constraint.
Note that the internal storage type of ENUM and SET changed in
tables created with >= InnoDB-4.1.12, and such columns in old tables
cannot be referenced by such columns in new tables.
See http://dev.mysql.com/doc/refman/5.1/en/innodb-foreign-key-constraints.html
for correct foreign key definition.
------------
I searched around on StackOverflow and elsewhere online - came across a helpful blog post here with pointers on how to resolve this error - but I can't figure out what's going wrong. Any help would be appreciated!