Error prevention by empty DB's request

rubyonrails-talk
1

Hi

I have often the problem that rails outputs an error because of requests from an empty database.

I will check, before showing features on the page, if a flag is set in the database. The problem is, that the DB is not filled, if you dont add the flag before. The result if i am doing the request is a nil object.

For example:

2

nil returns false, so

if @tourscheduler_user.tourscheduler_id && @tourscheduler_user.tourscheduler_id == @tourscheduler.id then   ...id and matching... else   ...no id or not matching... end

But there are several issues with this approach. 1) if you use tourscheduler_id, then there should always be a tourscheduler matching it Otherwise your db is inconsistent. If you delete a tourscheduler you should make sure, it's not referenced anymore...

2) It's not very rails like You should define belongs_to :tourscheduler in tourscheduler_user model and has_many :tourscheduler_users in tourscheduler model and use the rails methods to handle the ralationship. Then your code would be simply:

if @tourscheduler_user.tourscheduler then ... else ... end

3

hi Thorsten

Thanks a lot for the answere!!!

I follow your two points but the problem is still there.