[LRUG] How to do a db backed enum... or what should I be using...

[Chris Kimpton]

Hi,

Could I pick your brains a little...

I have some status values that I want to store in the DB, but also be
available in an enum-like way (perhaps that is my mistake...)

My current code is like this:

class Category < ActiveRecord::Base

  has_many :widgets

  def self.CAT1
    find_by_cat_name("cat1")
  end

end

This seems to work fine on its own, and when used via the console.

I'd like to use it in a "scope" to restrict a widget query, like so:


class Widget < ActiveRecord::Base

  belongs_to :category

  scope :one, where(:category_id => Category.CAT1).order(:created_at)

end

Again, this works fine in the console, I can add widgets to the category
and the scope picks up the new values.

But when I try the same via my tests, it is not finding the newly created
widgets.  From the logs, it seems the Category id is not set - as if the
scope is using an uninitialised version of the Category object.

  test "scope" do
    assert_equal 0, Widget.all.count
    assert_equal 0, Widget.one.count
    assert_equal 0, Widget.two.count
    assert_not_nil Category.CAT1
    assert_not_nil Category.CAT2
    Widget.create(:name => "foo", :size => 2, :category => Category.CAT2)
    assert_equal 1, Widget.all.count
    assert_equal 0, Widget.one.count
    assert_equal 1, Widget.two.count  # this assert fails - gets a 0.

  end

Perhaps I am doing something wrong...

The full (test) project is here -
https://github.com/kimptoc/scope-enum-tester - using Rails 3.1 (not tried
3.0 to see if that could be the issue...)

Thanks,
Chris