new

# File activerecord/lib/active_record/errors.rb, line 320
    def initialize(model = nil, description = nil)
      if model
        message = "Unknown primary key for table #{model.table_name} in model #{model}."
        message += "\n#{description}" if description
        @model = model
        super(message)
      else
        super("Unknown primary key.")
      end
    end