Removing a model in rails (reverse of “rails g mod

问题:

rails g model Rating user_id:integer message:string value:integer

How can I completely remove this model? Thanks

回答1:

bundle exec rake db:rollback    
rails destroy model <model_name>

When you generate a model, it creates a database migration. If you run 'destroy' on that model, it will delete the migration file, but not the database table. So before run

bundle exec rake db:rollback

回答2:

Try this

rails destroy model Rating

It will remove model, migration, tests and fixtures

回答3:

For future questioners: If you can't drop the tables from the console, try to create a migration that drops the tables for you. You should create a migration and then in the file note tables you want dropped like this:

class DropTables < ActiveRecord::Migration
  def up
    drop_table :table_you_dont_want
  end

  def down
    raise ActiveRecord::IrreversibleMigration
  end
end

回答4:

1. To remove migration (if you already migrated the migration)

   rake db:migrate:down VERSION="20130417185845" #Your migration version
   

2. To remove Model

   rails d model name  #name => Your model name
   

回答5:

Here's a different implementation of Jenny Lang's answer that works for Rails 5.

First create the migration file:

bundle exec be rails g migration DropEpisodes

Then populate the migration file as follows:

class DropEpisodes < ActiveRecord::Migration[5.1]
  def change
    drop_table :episodes
  end
end

Running rails db:migrate will drop the table. If you run rails db:rollback, Rails will throw a ActiveRecord::IrreversibleMigration error.