Error prevention by empty DB's request

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:

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

hi Thorsten

Thanks a lot for the answere!!!

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