[mysql] Error Code: 1005. Can't create table '...' (errno: 150)

I searched for a solution to this problem on the Internet and checked the Stack Overflow questions, but none of the solutions worked for my case.

I want to create a foreign key from table sira_no to metal_kod.

ALTER TABLE sira_no
    ADD CONSTRAINT METAL_KODU FOREIGN KEY(METAL_KODU)
    REFERENCES metal_kod(METAL_KODU)
    ON DELETE SET NULL
    ON UPDATE SET NULL ;

This script returns:

Error Code: 1005. Can't create table 'ebs.#sql-f48_1a3' (errno: 150)

I tried adding an index to the referenced table:

CREATE INDEX METAL_KODU_INDEX ON metal_kod (METAL_KODU);

I checked METAL_KODU on both tables (charset and collation), but I couldn't find a solution to this problem. How can I fix this problem?

Here is the metal_kod table:

METAL_KODU    varchar(4)    NO    PRI
DURUM    bit(1)    NO
METAL_ISMI    varchar(30)    NO
AYAR_YOGUNLUK    smallint(6)    YES        100

Sometimes it is due to the master table is dropped (maybe by disabling foreign_key_checks), but the foreign key CONSTRAINT still exists in other tables. In my case I had dropped the table and tried to recreate it, but it was throwing the same error for me.

So try dropping all the foreign key CONSTRAINTs from all the tables if there are any and then update or create the table.

Very often it happens when the foreign key and the reference key don't have the same type or same length.

check both tables has same schema InnoDB MyISAM. I made them all the same in my case InnoDB and worked

I had the very same error message. Finally I figured out I misspelled the name of the table in the command:

ALTER TABLE `users` ADD FOREIGN KEY (country_id) REFERENCES country (id);

versus

ALTER TABLE `users` ADD FOREIGN KEY (country_id) REFERENCES countries (id);

I wonder why on earth MySQL cannot tell such a table does not exist...

It happened in my case, because the name of the table being referenced in the constraint declaration wasn't correct (I forgot the upper case in the table name):

ALTER TABLE `Window` ADD CONSTRAINT `Windows_ibfk_1` FOREIGN KEY (`WallId`) REFERENCES `Wall` (`id`) ON DELETE CASCADE ON UPDATE CASCADE;

The foreign key has to have the exact same type as the primary key that it references. For the example has the type “INT UNSIGNED NOT NULL” the foreing key also have to “INT UNSIGNED NOT NULL”

CREATE TABLE employees(
id_empl INT UNSIGNED NOT NULL AUTO_INCREMENT,
PRIMARY KEY(id)
);
CREATE TABLE offices(
id_office INT UNSIGNED NOT NULL AUTO_INCREMENT,
id_empl INT UNSIGNED NOT NULL,
PRIMARY KEY(id),
CONSTRAINT `constraint1` FOREIGN KEY (`id_empl`) REFERENCES `employees` (`id_empl`) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='my offices';

Error Code: 1005

I had a similar issue, so here are few things that I did try (not in any order, except for the solution :) )

1. Changed the foreign key names (it didn't work)
2. Reduced the foreign key length
3. Verified the datatypes (darn nothing wrong)
4. Check indexes
5. Check the collations (everything fine, darn again)
6. Truncated the table, of no good use
7. Dropped the table and re-created
8. Tried to see if any circular reference is being created --- all fine

9. Finally, I saw that I had two editors open. One that in PhpStorm (JetBrains) and the other MySQL workbench. It seems that the PhpStorm / MySQL Workbench creates some kind of edit lock.

   I closed PhpStorm just to check if locking was the case (it could have been the other way around). This solved my problem.

In my case, it happened when one table is InnoB and other is MyISAM. Changing engine of one table, through MySQL Workbench, solves for me.

I had a similar error. The problem had to do with the child and parent table not having the same charset and collation. This can be fixed by appending ENGINE = InnoDB DEFAULT CHARACTER SET = utf8;

CREATE TABLE IF NOT EXISTS `country` (`id` INT(11) NOT NULL AUTO_INCREMENT,...) ENGINE = InnoDB DEFAULT CHARACTER SET = utf8;

... on the SQL statement means that there is some missing code.

MyISAM has been just mentioned. Simply try adding ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ; at the end of a statement, assuming that your other tables were created with MyISAM.

CREATE TABLE IF NOT EXISTS `tablename` (
  `key` bigint(20) NOT NULL AUTO_INCREMENT,
  FOREIGN KEY `key` (`key`) REFERENCES `othertable`(`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ;

This could also happen when exporting your database from one server to another and the tables are listed in alphabetical order by default.
So, your first table could have a foreign key of another table that is yet to be created. In such cases, disable foreign_key_checks and create the database.

Just add the following to your script:

SET FOREIGN_KEY_CHECKS=0;

and it shall work.

My problem was not listed, it was something so silly ..... The table that has the FK as PK was a composite PK that was declared like this: primary key (CNPJ, CEP) I wanted the CEP field to be FK in another table and I was stuck in this error, the moral of the story just inverted the code above for Primary key (CEP, CNPJ) and it worked. Get tip their friends.