rake db:rollback not working?

Question

I\'m writing my first Rails app. I\'ve run a few rails generate model ... and rake db:migrate commands, but I now want to change my data model and

Answer 1

NOTE: Use the suggestions with caution, it is very dangerous for non-dev environments.

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If

rake db:migrate:status

gives you a migration that says

up 20120702151447 ********** NO FILE **********

Then the best thing to do would be to do a (note that the following command will drop the database):

rake db:reset

to redo all migrations. If the last migration is the one missing, then schema.rb will have the last migration that rake db:migrate will look for:

ActiveRecord::Schema.define(:version => 20120702151447) do

Change that number to the last one in your migrate folder.

Answer 2

Solution (see my comment): run

rake db:migrate:status

and correct problems you find there. In this case (per @MarkThomas' followup), you might want to check all files you need are in place.

Answer 3

This is what worked for me. Combine the steps given in this answer and comment by dB.

1. run rake db:migrate:status
2. If you have a ****NO FILE**** entry, just note the version number as noFileVersion. Note the version of the entry just above no file entry(stable_version).
3. created a "dummy" file with name noFileVersion_create_nothing.rb, and body

class CreateNothing < ActiveRecord::Migration 
  def change 
  end 
end

4. run rake db:migrate VERSION=stable_version
5. remove the noFileVersion_create_nothing.rb manually.
6. run rake db:migrate.
7. run rake db:migrate:status again to check if No file entry has disappeared.

Answer 4

The following worked for me: rake db:migrate:down VERSION=20190304092208

Version number can be obtained by the following command: rake db:migrate:status

This was the last version number to rollback one last migration