find_one

# File activerecord/lib/active_record/relation/finder_methods.rb, line 275
    def find_one(id)
      id = id.id if ActiveRecord::Base === id

      column = columns_hash[primary_key]
      substitute = connection.substitute_at(column, bind_values.length)
      relation = where(table[primary_key].eq(substitute))
      relation.bind_values += [[column, id]]
      record = relation.take

      raise_record_not_found_exception!(id, 0, 1) unless record

      record
    end