def matching(staging_record, table_name = nil)
      table_name, id = Stagehand::Key.generate(staging_record, :table_name => table_name)
      prepare_to_modify(table_name)
      return Record.where(:id => id)
    end
def matching(staging_record, table_name = nil)
      table_name, id = Stagehand::Key.generate(staging_record, :table_name => table_name)
      prepare_to_modify(table_name)
      return Record.where(:id => id)
    end
Returns a scope that limits results any occurrences of the specified record.
 Record can be specified by passing a staging record, or an id and table_name.