relationships and delete

I have a cars table and photos table. One car can have many photos, i
specified the relationships, everything seems to work. Why if i destroy
the car object, it doesnt destroy all the images of that car in the
photos table? is it possible or i have to write a seprate line to take
care of that?

In your model's :has_many, add this:

:dependent - if set to :destroy all the associated objects are destroyed alongside this object by calling their destroy method. If set to :delete_all all associated objects are deleted without calling their destroy method. If set to :nullify all associated objects. foreign keys are set to NULL without calling their save callbacks. NOTE: :dependent => true is deprecated and has been replaced with :dependent => :destroy. May not be set if :exclusively_dependent is also set.

http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html#M000530