Question

I’m trying to convert a string to a time using DateTime.parse in a scope however, I’m getting an undefined local variable error.

Is it possible to convert a field within a scope or do I need to try something else?

My scope:

  scope :time_range, lambda {
    a = DateTime.parse(start_time_am)
    where("#{a} <= ?", Time.now.strftime('%H'))
  }  

— UPDATE —

Having played around with this, I’ve discovered I should probably overwrite the default accessor. I now have the following:

  def start_time_am
    read_attribute(:start_time_am).strftime("%H%M").to_i
  end

In the console, my start_time_am field now looks like:

 Promotion.last.start_time_am
  => 430 

However, if I wanted to define a new field temporarily so I can still use the initial one.

I can access this in the console but not when searching. Eg.

   def start_time_new
     read_attribute(:start_time_am).strftime("%H%M").to_i
   end

  def self.time_range
    time = Time.now.strftime('%H%M').to_i
    where("start_time_new <= ?", time)
  end

Gives a unknown column error. I thought attr_reader would solve but it’s not working.

Thanks

Answer 1

If you rewrite this as an equivalent method definition then it might be easier to figure out.

def self.time_range
  a = DateTime.parse(start_time_am)
  where("#{a} <= ?", Time.now.strftime('%H'))
end

Where is start_time_am coming from? The method doesn’t have any arguments.