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
              


        

Answer 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

Answer 2

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

Answer 3

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

Answer 4

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.