Alter table does not add the foreign key restraint

Question

I've exported a database from Access to a MySQL server (local)

While doing this it did not export the foreign keys I had assigned in the database with them. While inconvenient I thought it didn't matter since I could add them manually. However when I use the following command:

alter table betalingsstatus 
add foreign key (bedrijf_id) 
references bedrijven(bedrijf_id)

It says it successfully did add the constraint. However when I insert something into the table and I add a number that isn't in the table bedrijven it still inserts it. I had the same problem with other foreign keys I have in the database.

Answer 1

Put ENGINE=INNODB; after the creation - altering of those tables that you want to enforce the foreign key constraints.

Example:

CREATE TABLE mytbl
(
id int PRIMARY KEY AUTO_INCREMENT,
name varchar(10) NOT NULL
) ENGINE=INNODB;