id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
25140	Error when running test with MySQL database	luccascorrea	nobody	"I am running into this error when I try to test an app using a MySQL database. I get an IntegrityError(1215, 'Cannot add foreign key constraint')"" while creating the tables.

What is happenning is this: I have a model called SyncLog which has a foreign key to another model called UserEmployee. The error happens when this foreign key is added.

I checked the history of queries run by Django while creating the table and the results are below shown. What I can see is that Django starts creating the SyncLog table before the UserEmployee table and, because that table does not exist yet, the creation fails. I would suppose that there is a bug when determining the dependencies between models in order to determine the order the tables should be created.



{{{
CREATE DATABASE `test_compras`
set autocommit=0
set autocommit=1
SET SQL_AUTO_IS_NULL = 0
SHOW FULL TABLES
CREATE TABLE `django_migrations` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `app` varchar(255) NOT NULL, `name` varchar(255) NOT NULL, `applied` datetime(6) NOT NULL)
SELECT engine FROM information_schema.tables WHERE table_name = \django_migrations\
SELECT `django_migrations`.`app`, `django_migrations`.`name` FROM `django_migrations`
SHOW FULL TABLES
set autocommit=0
CREATE TABLE `e89_syncing_synclog` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `user_id` integer NOT NULL, `timestamp` datetime(6) NOT NULL, `identifier` varchar(100) NOT NULL)
SELECT engine FROM information_schema.tables WHERE table_name = \e89_syncing_synclog\
CREATE TABLE `e89_tools_keyvaluestore` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `key` varchar(255) NOT NULL UNIQUE, `value` longtext NOT NULL)
SELECT engine FROM information_schema.tables WHERE table_name = \e89_tools_keyvaluestore\
CREATE TABLE `e89_push_messaging_device` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `owner_id` integer NOT NULL, `registration_id` varchar(200) NOT NULL, `platform` varchar(30) NOT NULL, UNIQUE (`registration_id`, `platform`))
SELECT engine FROM information_schema.tables WHERE table_name = \e89_push_messaging_device\
CREATE TABLE `e89_beta_testing_betatester` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `email` varchar(255) NOT NULL UNIQUE, `name` varchar(255) NOT NULL, `platform` varchar(30) NULL, `udid` varchar(255) NULL, `phone` varchar(20) NOT NULL, `token` varchar(50) NOT NULL)
SELECT engine FROM information_schema.tables WHERE table_name = \e89_beta_testing_betatester\
CREATE TABLE `e89_beta_testing_iphonebetaapp` (`id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY, `plist_url` varchar(300) NULL, `ipa` varchar(100) NOT NULL, `plist` varchar(100) NOT NULL)
SELECT engine FROM information_schema.tables WHERE table_name = \e89_beta_testing_iphonebetaapp\
ALTER TABLE `e89_syncing_synclog` ADD CONSTRAINT `e89_syncing_user_id_670069ad1cf9eaae_fk_accounts_useremployee_id` FOREIGN KEY (`user_id`) REFERENCES `accounts_useremployee` (`id`)
rollback
set autocommit=1
}}}


The stacktrace I get is pasted below:


{{{
IntegrityError: (1215, 'Cannot add foreign key constraint')
  File ""raven/contrib/django/management/__init__.py"", line 41, in new_execute
  File ""django/core/management/base.py"", line 444, in execute
  File ""django/core/management/commands/migrate.py"", line 179, in handle
  File ""django/core/management/commands/migrate.py"", line 317, in sync_apps
  File ""django/db/backends/utils.py"", line 64, in execute
  File ""django/db/utils.py"", line 97, in __exit__
  File ""django/db/backends/utils.py"", line 62, in execute
  File ""django/db/backends/mysql/base.py"", line 124, in execute
  File ""MySQLdb/cursors.py"", line 205, in execute
  File ""MySQLdb/connections.py"", line 36, in defaulterrorhandler
}}}


I ran the same test with Django 1.7.9 and it worked fine.

I am using Sentry to monitor exceptions and I have their full stack trace with variable values and all. I will not paste it here because it's too long and kind of hard to read but I will attach it as a separate file because I believe it could help identifying the cause of this bug.
"	Bug	closed	Database layer (models, ORM)	1.8	Release blocker	needsinfo			Unreviewed	0	0	0	0	0	0