varchar Migration question for Ruby on Rails

I have created a new table including a column "note". The default is varchar(255) I believe but I wish to have this column be a text area vs. a field and to allow more data. I imagine that I would make this change in ActiveRecord::Migration file but I am curious as to the format. Do I simply change the varchar(255) to varchar(1000) for example? (if so what is the format? def self.up create_table :

[h6n]

Railsでカラムが:stringだとvarchar(255)になるので255文字以上の文字列を突っ込みたいときは:text使えばいい。モデルのテスト書いて落ちるのを確認し、マイグレーションで:textに変更してテスト通るのを確認した方が良さそう。