Question

Possible Duplicate:
Rails primary key and object id

I am baffled as to why I cannot refer an object’s attributes; hope someone can help…

I need to build a hash that will associate Marker.marker_name with it’s id from the database, which are already stored (the record id will serve as a foreign key in another table).

So, first I retrieve the Marker record via this named scope:

class Marker < ActiveRecord::Base    
named_scope :by_name, lambda { |marker_name| 
    {:conditions => ["marker_name = ?", marker_name]}}

which is called from my Uploads model, like this (marker_name has the value “Amelogenin”):

this_marker = Marker.by_name(marker_name)

I know this worked, because when I Use the debugger, I can see what is in this_marker, which looks like:

(rdb:2) y this_marker

• !ruby/object:Marker attributes:
  created_at: 2011-03-14 22:21:27.244885
  updated_at: 2011-03-14 22:21:27.244885
  id: “11”
  marker_name: Amelogenin attributes_cache: {}

Yet, I cannot assign the record id in my hash, like this:

$markers[marker_name] = this_marker.id

I cannot seem to refer directly to the id in this way; because, even in the debugger, I get this error:

(rdb:2) p this_marker.id
(__DELEGATION__):2: warning: Object#id will be deprecated; use Object#object_id

Is there some kind of different Ruby syntax I need to be using or what? How can I associate the marker_name with its record id?

Thanks in advance….

Answer 1

This Marker.by_name(marker_name) returns an array of makers. You should write:

this_marker = Marker.by_name(marker_name).first