Question

change_column :posts, :ID, :string, :null => false

I have used this after the add_column but when i leave the value as empty it does not show any error. why and what can i do to capture the error?

Answer 1

You should use validation inside your model:

class Post < ActiveRecord::Base
  validates :column_name, presence: true
end

And it better to do not use :id to store some string. This column name is reserved in Rails.