Duplicate column name when migrating Django database

Question

I am trying to migrate my database:

E:\PhytonProgects\natarelke>python manage.py migrate
System check identified some issues:

WARNINGS:
?: (mysql.W002) MySQL Strict Mode is not set for database connection       'default'
    HINT: MySQL's Strict Mode fixes many data integrity problems in MySQL,     such as data truncation upon insertion, by escalating warnings into errors. It   is strongly recommended
you activate it. See: 
https://docs.djangoproject.com/en/1.10/ref/databases/#mysql-sql-mode
Operations to perform:
Apply all migrations: admin, auth, catalog, contenttypes, main, ordering,     registration, sessions, users
Running migrations:
Rendering model states... DONE
Applying catalog.0002_auto_20170219_2146...Traceback (most recent call last):
File "manage.py", line 22, in <module>
execute_from_command_line(sys.argv)

File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line   367, in execute_from_command_line
utility.execute()
File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 359, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\Python27\lib\site-packages\django\core\management\base.py", line 305, in run_from_argv
self.execute(*args, **cmd_options)
File "C:\Python27\lib\site-packages\django\core\management\base.py", line 356, in execute
output = self.handle(*args, **options)

File "C:\Python27\lib\site-packages\django\core\management\commands\migrate.py", line 202, in handle
targets, plan, fake=fake, fake_initial=fake_initial

File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 97, in migrate
state = self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)

File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 132, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)

File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 237, in apply_migration
state = migration.apply(state, schema_editor)
File "C:\Python27\lib\site-packages\django\db\migrations\migration.py", line 129, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
 File "C:\Python27\lib\site-packages\django\db\migrations\operations\fields.py", line 84, in database_forwards
field,
 File "C:\Python27\lib\site-packages\django\db\backends\mysql\schema.py", line 43, in add_field
super(DatabaseSchemaEditor, self).add_field(model, field)
 File "C:\Python27\lib\site-packages\django\db\backends\base\schema.py", line 409, in add_field
self.execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\backends\base\schema.py", line 112, in execute
cursor.execute(sql, params)
 File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 79, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 64, in execute
return self.cursor.execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 64, in execute
return self.cursor.execute(sql, params)
File "C:\Python27\lib\site-packages\django\db\backends\mysql\base.py", line 112, in execute
return self.cursor.execute(query, args)
File "C:\Python27\lib\site-packages\MySQLdb\cursors.py", line 205, in execute
self.errorhandler(self, exc, value)
File "C:\Python27\lib\site-packages\MySQLdb\connections.py", line 36, in defaulterrorhandler
raise errorclass, errorvalue
django.db.utils.OperationalError: (1060, "Duplicate column name 'user_id'")

When I try to run python manage.py migrate I got errors shown above. Can anybody help me fix them?

The error says "Duplicate column name 'user_id'". Do you already have tables in your database? — Chris
– Chris, Commented Feb 19, 2017 at 20:03
yeah i have it., but i don't whant drop it coz i have inserted informations — Сергей Потапов
– Сергей Потапов, Commented Feb 19, 2017 at 20:05
Does your current database schema match your migrations (or some version of your migrations)? — Chris
– Chris, Commented Feb 19, 2017 at 20:09
how i can check it? before do python. manage.py migrate i remove all mirgate files and than do python manage.py makemigrations — Сергей Потапов
– Сергей Потапов, Commented Feb 19, 2017 at 20:11
Where did your existing tables come from? Migrations only work from a known state, and by removing all migration files and generating new ones you've gotten out of sync… — Chris
– Chris, Commented Feb 19, 2017 at 20:20

Nitish Kumar Pal · Accepted Answer · 2018-07-07 14:23:19Z

1

It's a simple issue which I also faced. It's nothing big just an issue of migrate command. Usually, when you make new models or new tables, you re-run old migrations along with the newly created ones. Of which sometimes the Django confuses I suppose over here.

Easiest solution what I found was.

1st empty your recycle bin.
then go to your migrations folder or folders( in case you have more than one app)
temporarily delete ( send all migration files such as 0001_initial.py 0002_auto_20170621_1006 etc. all of them to recycle bin.
Then re-run the commands python manage.py makemigrations and python manage.py migrate

*step 3: is temporary del. here you can also go back to recycle bin easily restore it in one click. (so del is safe)

answered Jul 7, 2018 at 14:23

Nitish Kumar Pal

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Erick lxvi · Accepted Answer · 2019-01-20 07:30:52Z

1

I want to tell you my case. This only works if you be patient and you are sure about the changes. Django 2.1

{% for crash in crashes %}

python manage.py makemigrations
Locate the conflict file (In the question catalog.0002_auto_20170219_2146.py or something)
Remove (copy in other file or don't close the file) temporally the columns that already exists into the database . (This is what you must be patient :/ ).

{% endfor %}

python manage.py migrate
Undo the change in files.

That's all, works for me. Moral: if you found an conflict with migrate, you should fix it, dont remove all files.

answered Jan 20, 2019 at 7:30

Erick lxvi

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Comments

Udi · Accepted Answer · 2017-02-20 07:05:37Z

0

There is a problem either in your DB, or your migrations, or both. If this is a new project, deleting the DB and all migrations, and recreating them with makemigrations will probably get you out of trouble.

To save your data, you can try reverting to a models.py that matches your DB, and use dumpdata to export your data to a JSON file.

answered Feb 20, 2017 at 7:05

Udi

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