[Zope] how to search entire site from a sub dir?

[Jianping Zhu]

 I have a zope the dirctory structure is
 Root ->sub1f1->sub2f1->sub3f3
      ->sub1f2
      ->development->sundev->mydev

      I need to search entire site from mydev, i am trying to use
      Zcatalog to do it but after i created A zcatalog under mydev, i
      use find objects to put object to ZODB. but i can not find a way 
      to seach the entire site, is there a way to do that?
      Thanks