CODEWITHSUNDEEP
ruby-on-railsmodelmigration
Sreeraj Chundayil
Sreeraj Chundayil

Reputation: 5859

self.table_name is not working

I am trying to learn rails Active Record. Learnt that self.table_name can be used to rename a table which rails create default.

class Order < ActiveRecord::Base
    self.table_name = "ordered"
end

But when I run the migration first time , I still get the orders table, not the one which I mentioned in the string. What is the mistake done here?

migration:

class CreateOrders < ActiveRecord::Migration
  def change
    create_table :orders do |t|

      t.timestamps null: false
    end
  end
end

Upvotes: 2

Views: 4544

Answers (2)

ldlgds
ldlgds

Reputation: 191

As an addition to @richard-peck 's comment, the correct syntax for renaming a table from a migration is: rename_table

Upvotes: 0

Richard Peck
Richard Peck

Reputation: 76774

class CreateOrders < ActiveRecord::Migration
  def change
    create_table :ordered do |t|
      t.timestamps null: false
    end
  end
end

This will create an ordered table.

If you've already got your orders table, you can use the following:

$ rails g migration ChangeOrdersToOrdered

#db/migrate/change_orders_to_ordered_______.rb
class ChangeOrdersToOrdered < ActiveRecord::Migration
   rename_name :orders, :ordered
end

$ rake db:migrate

Tables != Classes

You have to remember that your migrations are not the same as your classes - they are mutually exclusive.

Although the naming conventions are similar, and Rails does a great job of linking the two, the fact remains that you can call your tables whatever you want -- it will have no bearing on your models unless you specifically designate the table tied to the model.

Setting self.table_name only sets the class that model will read (it's a class method):

Guesses the table name (in forced lower-case) based on the name of the class in the inheritance hierarchy descending directly from ActiveRecord::Base. So if the hierarchy looks like: Reply < Message < ActiveRecord::Base, then Message is used to guess the table name even when called on Reply. The rules used to do the guess are handled by the Inflector class in Active Support, which knows almost all common English inflections. You can add new inflections in config/initializers/inflections.rb.

This means that no matter what you refer to in your self.table_name, you are open to use whichever migrations you want.

Upvotes: 3

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