Can NOT insert data into database in migration?

I am using Rails 3. I don't know if it is the rule of rails that inside migration, it seems I can not insert data into database table. If someone can confirm it is so.

I tried the following things:

I have two ActiveRecord model:

class Car < ActiveRecord::Base
  has_many :users
  ...
end

class User < ActiveRecord::Base
  belongs_to :car
  ...
end

I have generate a migration file, inside the migration I have:

 def self.up
    default_car = Car.new({:name => 'default_car'})
    default_car.save() #I got 'false' here

    User.create!(:car_id => default_car.id}) #I got default_car.id is null value

  end

  def self.down
    default_car = Car.find({:name => 'default_car'})
    default_user = User.find({:car_id=>default_car.id})

    default_car.delete
    default_user.delete
  end

I 开发者_Go百科got false when I trying to save the default_car to database, and my default_user have null car_id.

Is it because in migration, it is NOT allowed to store data into database??

---

You can create data in migrations, however it is probably best not to, use seeds.rb instead.

Think the above will be failing because your car is not saving, I'm guessing you have some validation in your Car model.

---

Ok, we've figgured out that there was some validation issues. So you would like to now, that you can skip validations:

default_car = Car.new({:name => 'default_car'})
default_car.save(false)
#=> true