What does mysql error 1025 (HY000): Error on rename of './foo' (errorno: 150) mean?

Question

You usually get this error if your tables use the InnoDB engine. In that case you would have to drop the foreign key, and then do the alter table and drop the column.

But the tricky part is that you can't drop the foreign key using the column name, but instead you would have to find the name used to index it. To find that, issue the following select:

SHOW CREATE TABLE region;

This should show you the name of the index, something like this:

CONSTRAINT region_ibfk_1 FOREIGN KEY (country_id) REFERENCES country (id) ON DELETE NO ACTION ON UPDATE NO ACTION

Now simply issue an:

alter table region drop foreign key region_ibfk_1;

And finally an:

alter table region drop column country_id;

And you are good to go!

It is indeed a foreign key error, you can find out using perror:

shell$ perror 150
MySQL error code 150: Foreign key constraint is incorrectly formed

To find out more details about what failed, you can use SHOW ENGINE INNODB STATUS and look for the LATEST FOREIGN KEY ERROR section it contains details about what is wrong.

In your case, it is most likely cause something is referencing the country_id column.

You can get also get this error trying to drop a non-existing foreign key. So when dropping foreign keys, always make sure they actually exist.

If the foreign key does exist, and you are still getting this error try the following:

SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;
SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='TRADITIONAL';

// Drop the foreign key here!

SET SQL_MODE=@OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;

This always does the trick for me :)

Simply run the alter table query using 'KEY' instead of 'FOREIGN KEY' in the drop statement. I hope it will help to solve the issue, and will drop the foreign key constraint and you can change the table columns and drop the table.

ALTER TABLE slide_image_sub DROP  KEY  FK_slide_image_sub;

here in DROP KEY instead of DROP FOREIGN KEY,

hope it will help.

Thanks

I know, this is an old post, but it's the first hit on everyone's favorite search engine if you are looking for error 1025.

However, there is an easy "hack" for fixing this issue:

Before you execute your command(s) you first have to disable the foreign key constraints check using this command:

SET FOREIGN_KEY_CHECKS = 0;

Then you are able to execute your command(s).

After you are done, don't forget to enable the foreign key constraints check again, using this command:

SET FOREIGN_KEY_CHECKS = 1;

Good luck with your endeavor.

I had a similar issues once. I deleted the primary key from TABLE A but when I was trying to delete the foreign key column from table B I was shown the above same error.

You can't drop the foreign key using the column name and to bypass this in PHPMyAdmin or with MySQL, first remove the foreign key constraint before renaming or deleting the attribute.

Take a look in error file for your mysql database. According to Bug #26305 my sql do not give you the cause. This bug exists since MySQL 4.1 ;-)