Reputation: 5163

Rake just one migration

I'm trying to run just one migration out of a whole bunch in my rails app. How can I do this? I don't want to run any of the migrations before or after it. Thanks.

Upvotes: 104

Answers (11)

reshma

Reputation: 651

rake db:migrate:up VERSION=version_no

Will migrate( add) specific migration script

rake db:migrate:down VERSION=version_no

Will delete specific migration script

Upvotes: 20

Greg Blass

Reputation: 3650

I use this technique in development when I change a migration a significant amount, and I don't want to migrate down a ton and lose any data in those along the way (especially when I'm importing legacy data that takes a long time that I don't want to have to re-import again).

This is 100% hackish and I would definitely not recommend doing this in production, but it will do the trick:

Move migration that you want to re-run out of its directory to a temporary place
Generate another migration with the same name
Copy/paste the original migration code into the newly generated migration file
Run the new migration
Delete the newly generated migration file
Edit your schema migrations to remove the most recent value
Restore the old migration file

Upvotes: 0

Ken Simon

Reputation: 1544

Adding my 2¢ to this because I ran into this same issue:

If you absolutely want to run a migration over again without creating a new one, you can do the following:

rails dbconsole -p devdb=# delete from public.schema_migrations where version = '20150105181157';

And rails will "forget" that it ran the migration for 20150105181157. Now when you run db:migrate it will run it again.

This is almost always a bad idea though. The one instance where it could make sense is if you have a development branch and you haven't fleshed out your migration yet and want to add some things to it in development. But even then it's better to make your migration 2-way so you can properly rollback and retry repeatedly.

Upvotes: 3

hexinpeter

Reputation: 1570

rake db:migrate:redo version='xxxx'

Remember to put the quotation mark around xxxx, xxxx is the timestamp (or Migration ID) for your migration.

You may check the timestamps (Migration ID) for the previous migrations you've done by using

rake db:migrate:status

Upvotes: 5

bhfailor

Reputation: 183

Expanding on the answer by korch above, require did not work for me, but load did. To be concrete, for the migration file:

    class ChangeMinQuantityToRaces < ActiveRecord::Migration
      def change
        change_column :races, :min_quantity, :integer, :default => 0
      end
    end

in the console typing

    > load 'db/migrate/30130925110821_change_min_quantity_to_races.rb'
    > ChangeMinQuantityToRaces.new.change

worked for me.

    > Race.new.min_quantity # => 0

This was for ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux] and Rails 3.2.13.

Upvotes: 3

aceofspades

Reputation: 7586

I have a utility method that makes this very easy in development. I find that it helps me avoid creating too many migrations--normally I modify migrations until they have been deployed.

http://fullware.net/index.php/2011/05/26/easily-load-rails-migrations-for-console-execution/

Upvotes: 1

user46519

Reputation:

I've had to run a single migration that changed and needed to be re-run independently of all other migrations. Fire up the console and do this:

>> require 'db/migrate/your_migrations.rb'
=> ["YourMigrations"]
>> YourMigrations.up
=> etc... as the migration runs
>> YourMigration.down

More usefully this could be put into a rake task etc.

Upvotes: 26

Shadwell

Reputation: 34774

rake db:migrate:up VERSION=1234567890

similarly rake db:migrate:down to take a specific migration down. You can get a list of available rake tasks with rake -T.

Upvotes: 76

Ryan Bigg

Reputation: 107718

rake db:migrate:redo VERSION=xxxxxxx, but that will run the down and then the up step. You could do this in conjunction with commenting out the down step temporarily.

Upvotes: 174