# File lib/thinking_sphinx/active_record/join_association.rb, line 6
  def build_constraint(klass, table, key, foreign_table, foreign_key)
    constraint = super

    constraint = constraint.and(
      foreign_table[reflection.options[:foreign_type]].eq(
        base_klass.base_class.name
      )
    ) if reflection.options[:sphinx_internal_filtered]

    constraint
  end