ruby-on-rails - How do I describe a relationship like "issue has status" in Rails 3?

Question

I am developing an "issue tracker" app in Rails 3 but I am having trouble describing the relationship between an "Issue" and its "Status". Each issue can only have one status - I'd like this to be a combo box in HTML - but clearly each status can be assigned to multiple issues. I started with "issue has one status" but then I ran into problems retrieving that status in the view. I assume this is correct, but I must need something else...

Answer 1

In this case an issue belongs to a certain status:

class Issue
  belongs_to :status
end

Think of status as a type of category that each issue belongs to.

Answer 2

If you won't be allowing a custom status, it makes more sense to have the all status' as a constant array (used for select) and a status string field in issues. You will still be able to list all issues with a status with a scope.

Update for the question

class Issue
    STATUSES = [ "Open", "Closed" ]

    scope :with_status, lambda { |status| where(:status => [*status]) }
end

In view,

<%= f.select :status, Issue::STATUSES %>

You'll need a field in the database. So in a migration:

add_column :issues, :status, :string

To find Issues with status in controller:

@open_issues = Issue.with_status("Open").all;
@current_issues = Issue.with_status([ "Pending", "Waiting on Review"]).all;

Or with an association:

@closed_issues = @project.issues.with_status("Closed");

Answer 3

You should be using Issue belongs_to :status and Status has_many :issues instead.

When you use a has_one association, Rails will look for the foreign key issue_id in the statuses table. This is not what you want. You want issues to point to statuses, not vice versa.