Question

I have a Pages table in my DB with a field called position.

How can I increase that value by one before it’s saved?

Even better how can I remove unused positions and give the new record the correct position number?

Answer 1

You need a before_save callback:

In your Page model:

before_save :increase_position

def increase_position
  self.position += 1
end

You can add any kind of logic to the increase_position method to remove unused positions.