change column name Rails

Question

I have this table:

class CreateShoes < ActiveRecord::Migration
  def change
    create_table :shoes do |t|
      t.string :name
      t.boolean :leather
      t.integer :season

      t.timestamps null: false
    end
  end
end

the 'season' column should be called 'season_id'. I know that I have to write 't.rename :season, :season_id' as explained in http://edgeguides.rubyonrails.org/active_record_migrations.html#column-modifiers but I don't manage to find the right syntax. Should it be?

class CreateShoes < ActiveRecord::Migration
  def change
    create_table :shoes do |t|
      t.string :name
      t.boolean :leather
      t.integer :season

      t.timestamps null: false
    end

    change_table :products do |t|
      t.rename :season, :season_id
    end

  end
end

Doesn't work. Anything I have to do in the Mac console? Thanks!

Why are you renaming it in the same migration? Either rollback and fix it in the create_table, or create a new migration. You can also just write rename_column :shoes, :season, :season_id instead of putting it in a block. — Dave Newton
– Dave Newton, Commented Jan 14, 2016 at 18:00
I don't quite know what I doing. learning :) forgot to add that the table has data in it. create new migration means a new 'def change'? thx — aixecador
– aixecador, Commented Jan 14, 2016 at 18:04

Inpego · Accepted Answer · 2016-01-14 18:21:09Z

69

Run in your console:

$ rails g migration rename_season_to_season_id

Now file db/migrate/TIMESTAMP_rename_season_to_season_id.rb contains following:

class RenameSeasonToSeasonId < ActiveRecord::Migration
  def change
  end
end

Modify it as follows:

class RenameSeasonToSeasonId < ActiveRecord::Migration
  def change
    rename_column :shoes, :season, :season_id
  end
end

Then run $ rake db:migrate in console.

edited Jan 14, 2016 at 18:21

answered Jan 14, 2016 at 18:15

Inpego

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Comments

ruby_newbie · Accepted Answer · 2016-01-14 18:12:31Z

5

Either fix your migration and do

rake db:rollback db:migrate

or make another migration like so:

rename_column :shoes, :season, :season_id if column_exists?(:shoes, :season) && !column_exists?(:shoes, :season_id)

and then do

rake db:migrate

answered Jan 14, 2016 at 18:12

ruby_newbie

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Comments

dixpac · Accepted Answer · 2017-02-27 13:54:57Z

If your intention is to rename column in table than you example migration is not making sense :)... Instead of this

class CreateShoes < ActiveRecord::Migration
  def change
    create_table :shoes do |t|
      t.string :name
      t.boolean :leather
      t.integer :season

      t.timestamps null: false
    end

    change_table :products do |t|
      t.rename :season, :season_id
    end

  end
end

You just need table change migration, like this(Rails will take care rollback for your):

class RenameSessionColumnInsideShoes < ActiveRecord::Migration
  def change
    change_table :products do |t|
      t.rename :season, :season_id
    end
  end
end

rename method on table object in rails is valid method, as you can see in Rails source code

https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb#L582

Sushant · Accepted Answer · 2020-01-29 06:26:13Z

1

If your branch has been pushed to production then one probably needs to add the new migration by running the following command:

rails g migration RenameSeasonColumnNameToShoes

and if it hasn't been pushed to production or you have to currently make changes to your branch only, then do:

bundle exec rake db:rollback

Then make changes to your migration file inside /db/migrate/<your_migration_file_name>

Then in your migration file, using rename_column do as follows:

class RenameSeasonColumnNameToShoes < ActiveRecord::Migration
  def change
      rename_column :shoes, :season, :season_id
  end
end

and then do

bundle exec rake db:migrate db:test:prepare

answered Jan 29, 2020 at 6:26

Sushant

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