Rails help model design problem

I am having that problem when I update my konkurrencer the do_foobar is called. The problem is that the konkurrancer have no ratings. And I get a off course a开发者_C百科 ZeroDivisionerror.

What is the best solution to solve this kind of problem?

My model:

before_update :do_foobar
def do_foobar
  self.rating = (rating_score/ratings)
end

self.rating = (ratings == 0) ? nil : rating_score/ratings

or

self.rating = rating_score/ratings rescue nil

if you always do

self.rating = 0 if ratings == 0 else (rating_score/ratings)

A simpler way would be to catch the error on the spot.

rating = rating_score - ratings rescue 0

This will instantly catch the ZeroDivisionError and pass the 0 through. (Be careful though. It will also catch and rescue any other error happening inside your rating_score and ratings calls)

Another season, another reason, to love Ruby :)

You have to initialize this value before use, for example like this:

def do_foobar
  self.rating |= 1
  self.rating = (rating_score/rating)
end

What about:

rating = rating_score/ratings if ratings != 0