MySQL: Can't create table (errno: 150)

Question

I am trying to import a .sql file and its failing on creating tables.

Here\'s the query that fails:

CREATE TABLE `data` (
`id` int(10) unsigned NOT NUL         


        

Answer 1

I had a similar problem but mine was because i was adding a new field to an existing table that had data , and the new field was referencing another field from the parent table and also had the Defination of NOT NULL and without any DEFAULT VALUES. - I found out the reason things were not working was because

1. My new field needed to autofill the blank fields with a value from the parent table on each record, before the constraint could be applied. Every time the constraint is applied it needs to leave the Integrity of the table data intact. Implementing the Constraint (Foreign Key) yet there were some database records that did not have the values from the parent table would mean the data is corrupt so MySQL would NEVER ENFORCE YOUR CONSTRAINT

It is important to remember that under normal circumstances if you planned your database well ahead of time, and implemented constraints before data insertion this particular scenario would be avoided

The easier Approach to avoid this gotcha is to

• Save your database tables data
• Truncate the table data (and table artifacts i.e indexes etc)
• Apply the Constraints
• Import Your Data

I Hope this helps someone