How to revert the last migration

Question

I ve made a migration that added a new table and want to revert it and delete the migration  without creating a new migration   How do I do it  Is there a command to revert last migration and then I can simply delete the migration file

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This answer is for similar cases if the top answer by Alasdair does not help   E g  if the unwanted migration is created soon again with every new migration or if it is in a bigger migration that can not be reverted or the table has been removed manually          delete the migration  without creating a new migration    TL DR  You can delete a few last reverted  confused  migrations and make a new one after fixing models  You can also use other methods to configure it to not create a table by migrate command  The last migration must be created so that it match the current models     Cases why anyone do not want to create a table for a Model that must exist   A  No such table should exist in no database on no machine and no conditions   When  It is a base model created only for model inheritance of other model  Solution  Set class Meta  abstract   True   B  The table is created rarely  by something else or manually in a special way    Solution  Use class Meta  managed   False The migration is created  but never used  only in tests  Migration file is important  otherwise database tests can t run  starting from reproducible initial state    C  The table is used only on some machine  e g  in development     Solution  Move the model to a new application that is added to INSTALLED APPS only under special conditions or use a conditional class Meta  managed   some switch    D  The project uses multiple databases in settings DATABASES   Solution  Write a Database router with method allow migrate in order to differentiate the databases where the table should be created and where not      The migration is created in all cases A   B   C   D  with Django 1 9   and  only in cases B  C  D with Django 1 8   but applied to the database only in appropriate cases or maybe never if required so  Migrations have been necessary for running tests since Django 1 8  The complete relevant current state is recorded by migrations even for models with managed False in Django 1 9  to be possible to create a ForeignKey between managed unmanaged models or to can make the model managed True later   This question has been written at the time of Django 1 8  Everything here should be valid for versions between 1 8 to the current 2 2    If the last migration is  are  not easily revertible then it is possible to cautiously  after database backup  do a fake revert   manage py migrate --fake my app 0010 previous migration  delete the table manually   If necessary  create a fixed migration from the fixed model and apply it without changing the database structure   manage py migrate --fake my app 0011 fixed migration

User · Answer

You can revert by migrating to the previous migration   For example  if your last two migrations are    0010 previous migration 0011 migration to revert   Then you would do     manage py migrate my app 0010 previous migration    You can then delete migration 0011 migration to revert   If you re using Django 1 8   you can show the names of all the migrations with    manage py showmigrations my app   To reverse all migrations for an app  you can run     manage py migrate my app zero

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The other thing that you can do is delete the table created manually    Along with that  you will have to delete that particular migration file  Also  you will have to delete that particular entry in the django-migrations table probably the last one in your case  which correlates to that particular migration

User · Answer

To revert a migration  python manage py migrate  lt APP NAME gt   lt MIGRATION NUMBER PREFIX gt   MIGRATION NUMBER PREFIX is the number prefix of the migration you want to revert to  for instance 0001 to go to 0001 initial py migration  then you can delete that migration   You can use zero as your migration number to revert all migrations of an app

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If you are facing trouble while reverting back the migration  and somehow have messed it  you can perform fake migrations     manage py migrate  lt name gt  --ignore-ghost-migrations --merge --fake   For django version  lt  1 7 this will create entry in south migrationhistory table  you need to delete that entry   Now you ll be able to revert back the migration easily   PS  I was stuck for a lot of time and performing fake migration and then reverting back helped me out

User · Answer

The answer by Alasdair covers the basics   Identify the migrations you want by   manage py showmigrations migrate using the app name and the migration name   But it should be pointed out that not all migrations can be reversed  This happens if Django doesn t have a rule to do the reversal  For most changes that you automatically made migrations by   manage py makemigrations  the reversal will be possible  However  custom scripts will need to have both a forward and reverse written  as described in the example here   https   docs djangoproject com en 1 9 ref migration-operations   How to do a no-op reversal  If you had a RunPython operation  then maybe you just want to back out the migration without writing a logically rigorous reversal script  The following quick hack to the example from the docs  above link  allows this  leaving the database in the same state that it was after the migration was applied  even after reversing it     - - coding  utf-8 - - from   future   import unicode literals  from django db import migrations  models  def forwards func apps  schema editor         We get the model from the versioned app registry        if we directly import it  it ll be the wrong version     Country   apps get model  myapp    Country       db alias   schema editor connection alias     Country objects using db alias  bulk create           Country name  USA   code  us            Country name  France   code  fr            class Migration migrations Migration        dependencies           operations             migrations RunPython forwards func  lambda apps  schema editor  None           This works for Django 1 8  1 9    Update  A better way of writing this would be to replace lambda apps  schema editor  None with migrations RunPython noop in the snippet above  These are both functionally the same thing   credit to the comments

User · Answer

You can revert by migrating to the previous migration  For example use below command    manage py migrate example app one left to the last migration  then delete last migration file

User · Answer

Here is my solution  since the above solution do not really cover the use-case  when you use RunPython   You can access the table via the ORM with  from django db migrations recorder import MigrationRecorder   gt  gt  gt  MigrationRecorder Migration objects all    gt  gt  gt  MigrationRecorder Migration objects latest  id   Out 5    lt Migration  Migration 0050 auto 20170603 1814 for model gt   gt  gt  gt  MigrationRecorder Migration objects latest  id   delete   Out 4    1   u migrations Migration   1     So you can query the tables and delete those entries that are relevant for you  This way you can modify in detail  With RynPython migrations you also need to take care of the data that was added changed removed  The above example only displays  how you access the table via Djang ORM

User · Answer

Don t delete the migration file until after the reversion  I made this mistake and without the migration file  the database didn t know what things to remove     python manage py showmigrations python manage py migrate  app name from show migrations   00   migration file py    Delete the migration file   Once the desired migration is in your models     python manage py makemigrations python manage py migrate

User · Answer

I did this in 1 9 1  to delete the last or latest migration created     rm  lt appname gt  migrations  lt migration   gt    example  rm myapp migrations 0011  logged into database and ran this SQL  postgres in this example   delete from django migrations where name like  0011      I was then able to create new migrations that started with the migration number that I had just deleted  in this case  11

User · Answer

there is a good library to use its called djagno-nomad  although not directly related to the question asked  thought of sharing this  scenario   most of the time when switching to project  we feel like it should revert our changes that we did on this current branch  that s what exactly this library does  checkout below https   pypi org project django-nomad

[django] How to revert the last migration?

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