relation_for_destroy

# File activerecord/lib/active_record/locking/optimistic.rb, line 124
        def relation_for_destroy
          relation = super

          if locking_enabled?
            column_name = self.class.locking_column
            column      = self.class.columns_hash[column_name]
            substitute  = self.class.connection.substitute_at(column)

            relation = relation.where(self.class.arel_table[column_name].eq(substitute))
            relation.bind_values << [column, self[column_name].to_i]
          end

          relation
        end