Rails: How do I create a default value for attributes in Rails activerecord's model?

Question

I want to create a default value for an attribute by defining it in ActiveRecord. By default everytime the record is created, I want to have a default value for attribute :status. I tried to do this:

class Task < ActiveRecord::Base
  def status=(status)
    status = 'P'
    write_attribute(:status, status)
  end
end

But upon creation I still retrieve this error from the database:

ActiveRecord::StatementInvalid: Mysql::Error: Column 'status' cannot be null

Therefore I presume the value was not applied to the attribute.

What would be the elegant way to do this in Rails?

Many thanks.

Answer 1

You can set a default option for the column in the migration

....
add_column :status, :string, :default => "P"
....

OR

You can use a callback, before_save

class Task < ActiveRecord::Base
  before_save :default_values
  def default_values
    self.status ||= 'P' # note self.status = 'P' if self.status.nil? might be safer (per @frontendbeauty)
  end
end