I have the following migration file db\migrate\20100905201547_create_blocks.rb
How can I specifically rollback that migration file?
Class.down
stackoverflow.com/questions/753919/run-a-single-migration-file
rake db:rollback STEP=1
Is a way to do this, if the migration you want to rollback is the last one applied. You can substitute 1 for however many migrations you want to go back.
For example:
rake db:rollback STEP=5
Will also rollback all the migration that happened later (4, 3, 2 and also 1).
To roll back all migrations back to (and including) a target migration, use: (This corrected command was added AFTER all the comments pointing out the error in the original post)
rake db:migrate VERSION=20100905201547
In order to rollback ONLY ONE specific migration (OUT OF ORDER) use:
rake db:migrate:down VERSION=20100905201547
Note that this will NOT rollback any interceding migrations -- only the one listed. If that is not what you intended, you can safely run rake db:migrate
and it will re-run only that one, skipping any others that were not previously rolled back.
And if you ever want to migrate a single migration out of order, there is also its inverse db:migrate:up
:
rake db:migrate:up VERSION=20100905201547
rake db:migrate:down VERSION=20100905201547
will roll back the specific file.
To find the version of all migrations, you can use this command:
rake db:migrate:status
Or, simply the prefix of the migration's file name is the version you need to rollback.
See the Ruby on Rails guide entry on migrations.
To rollback the last migration you can do:
rake db:rollback
If you want to rollback a specific migration with a version you should do:
rake db:migrate:down VERSION=YOUR_MIGRATION_VERSION
For e.g. if the version is 20141201122027, you will do:
rake db:migrate:down VERSION=20141201122027
to rollback that specific migration.
You can rollback your migration by using rake db:rollback
with different options. The syntax will be different according to your requirements.
If you want to rollback just the last migration, then you can use either
rake db:rollback
or
rake db:rollback STEP=1
If you want rollback number of migrations at once, then you simply pass an argument:
rake db:rollback STEP=n
where n
is number of migrations to rollback, counting from latest migration.
If you want to rollback to a specific migration, then you should pass the version of the migration in the following:
rake db:migrate:down VERSION=xxxxx
where xxxxx is the version number of the migration.
rake db:migrate:down VERSION=your_migrations's_version_number_here
The version is the numerical prefix on the migration's file name
How to find version:
Your migration files are stored in your rails_root/db/migrate
directory. Find appropriate file up to which you want to rollback and copy the prefix number.
for example
file name: 20140208031131_create_roles.rb
then the version is 20140208031131
rake db:migrate:status
Rolling back last migration:
# rails < 5.0
rake db:rollback
# rails >= 5.0
rake db:rollback
# or
rails db:rollback
Rolling back last n
number of migrations
# rails < 5.0
rake db:rollback STEP=2
# rails >= 5.0
rake db:rollback STEP=2
# or
rails db:rollback STEP=2
Rolling back a specific migration
# rails < 5.0
rake db:migrate:down VERSION=20100905201547
# rails >= 5.0
rake db:migrate:down VERSION=20100905201547
# or
rails db:migrate:down VERSION=20100905201547
To rollback the last migration you can do:
rake db:rollback
If you want to rollback a specific migration with a version you should do:
rake db:migrate:down VERSION=YOUR_MIGRATION_VERSION
If the migration file you want to rollback was called db/migrate/20141201122027_create_some_table.rb
, then the VERSION for that migration is 20141201122027
, which is the timestamp of when that migration was created, and the command to roll back that migration would be:
rake db:migrate:down VERSION=20141201122027
To roll back all migrations up to a particular version (e.g. 20181002222222
), use:
rake db:migrate VERSION=20181002222222
(Note that this uses db:migrate
-- not db:migrate:down
as in other answers to this question.)
Assuming the specified migration version is older than the current version, this will roll back all migrations up to, but not including, the specified version.
For example, if rake db:migrate:status
initially displays:
(... some older migrations ...)
up 20181001002039 Some migration description
up 20181002222222 Some migration description
up 20181003171932 Some migration description
up 20181004211151 Some migration description
up 20181005151403 Some migration description
Running:
rake db:migrate VERSION=20181002222222
Will result in:
(... some older migrations ...)
up 20181001002039 Some migration description
up 20181002222222 Some migration description
down 20181003171932 Some migration description
down 20181004211151 Some migration description
down 20181005151403 Some migration description
Reference: https://makandracards.com/makandra/845-migrate-or-revert-only-some-migrations
If it is a reversible migration and the last one which has been executed, then run rake db:rollback
. And you can always use version. e.g
the migration file is 20140716084539_create_customer_stats.rb,so the rollback command will be, rake db:migrate:down VERSION=20140716084539
From Rails Guide
Reverting Previous Migrations
You can use Active Record's ability to rollback migrations using the revert
method:
require_relative '20100905201547_create_blocks'
class FixupCreateBlock < ActiveRecord::Migration
def change
revert CreateBlock
create_table(:apples) do |t|
t.string :variety
end
end
end
The revert
method also accepts a block of instructions to reverse. This could be useful to revert selected parts of previous migrations. For example, let's imagine that CreateBlock is committed and it is later decided it would be best to use Active Record validations, in place of the CHECK constraint, to verify the zipcode.
class DontUseConstraintForZipcodeValidationMigration < ActiveRecord::Migration
def change
revert do
# copy-pasted code from CreateBlock
reversible do |dir|
dir.up do
# add a CHECK constraint
execute <<-SQL
ALTER TABLE distributors
ADD CONSTRAINT zipchk
CHECK (char_length(zipcode) = 5);
SQL
end
dir.down do
execute <<-SQL
ALTER TABLE distributors
DROP CONSTRAINT zipchk
SQL
end
end
# The rest of the migration was ok
end
end
end
The same migration could also have been written without using revert but this would have involved a few more steps: reversing the order of create_table and reversible, replacing create_table by drop_table, and finally replacing up by down and vice-versa. This is all taken care of by revert.
Migrations change the state of the database using the command
$ bundle exec rake db:migrate
We can undo a single migration step using
$ bundle exec rake db:rollback
To go all the way back to the beginning, we can use
$ bundle exec rake db:migrate VERSION=0
As you might guess, substituting any other number for 0 migrates to that version number, where the version numbers come from listing the migrations sequentially
If you want to rollback and migrate you can run:
rake db:migrate:redo
That's the same as:
rake db:rollback
rake db:migrate
Well in rails 5 it's quite easy rake db:migrate:status or rails db:migrate:status
It was modified to handle both the same way Then just pick which Version you want to roll back and then run rake db:migrate VERSION=2013424230423
Make sure VERSION is all capital letters
If you have a problem with any step of the migration or stuck in the middle simply go to the migration file and comment out the lines that were already migrated.
Hope that helps
i found these steps most useful.
To check for status, run rails db:migrate:status
. Then you'll have a good view of the migrations you want to remove.
Then, run rails db:rollback
to revert the changes one by one. After doing so, you can check the status again to be fully confident.
Next, if you want to remove or delete. Run rails d migration <migration_name>
. This would clean up the versions you created.
After that's done, you can proceed to making new changes.
If you using RAILS 3
Step: 1 (Check the last migration)
bundle exec rake db:migrate:status
Step: 2 (Rollback Last Migration)
bundle exec rake db:rollback
Now, you can revert migration with safety One by One.
For Specific Migration
rails d migration
For revert multiple migrations
bundle exec rake db:rollback STEP=n
n = how many migrations do you want to rollback
Example: bundle exec rake db:rollback STEP=5
In Addition
When migration you deployed long ago does not let you migrate new one.
What happened is, I work in a larger Rails app with more than a thousand of migration files. And, it takes a month for us to ship a medium-sized feature. I was working on a feature and I had deployed a migration a month ago then in the review process the structure of migration and filename changed, now I try to deploy my new code, the build failed saying
ActiveRecord::StatementInvalid: PG::DuplicateColumn: ERROR: column "my_new_field" of relation "accounts" already exists
none of the above-mentioned solutions worked for me because the old migration file was missing and the field I intended to create in my new migration file already existed in the DB. The only solution that worked for me is:
I scped the file to the server I opened the rails console I required the file in the IRB session then AddNewMyNewFieldToAccounts.new.down
then I could run the deploy build again.
Hope it helps you too.
For multiple databases configurations (RoR >= v6), you must append the database name in the command, like:
rails db:rollback:primary, where primary is the name of the database in your config/databases.yml file, to rollback the last migration. You can make usage of the STEPS attribute here, as usual.
rails db:rollback:primary VERSION=your_migration_timestamp, to rollback only the provided migration version. Here primary is the name of the database too.
If you Want to Revert from last Migration Use rake db:rollback command It's Work Fine for Me!
Success story sharing
STEP=-1
. I did that once and it went mad, rolling back everything. Not nice! This was Rails 4.2 - I guess it may be fixed by now.rake db:migrate:status
to see all the specific migrations and their status!