MySQL “ERROR 1005 (HY000): Can't create table 'foo.#sql-12c_4' (errno: 150)”

Question

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 t

Answer 1

Check that BOTH tables have the same ENGINE. For example if you have:

CREATE Table FOO ();

and:

CREATE Table BAR () ENGINE=INNODB;

If you try to create a constraint from table BAR to table FOO, it will not work on certain MySQL versions.

Fix the issue by following:

CREATE Table FOO () ENGINE=INNODB;

Answer 2

Solved:

Check to make sure Primary_Key and Foreign_Key are exact match with data types. If one is signed another one unsigned, it will be failed. Good practice is to make sure both are unsigned int.