Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> comp.databases.theory -> Re: Heirarchical Data Structures. MS Access. Together?

Re: Heirarchical Data Structures. MS Access. Together?

From: --CELKO-- <joe.celko_at_northface.edu>
Date: 28 Jul 2003 09:54:14 -0700
Message-ID: <a264e7ea.0307280854.61d7d42f@posting.google.com> 





>>  one should not allow removal of a parent (i.e. someone that has 

children)... any parent has (right - left - 1) / 2 = number of
children. <<



I usually use (lft = rgt -1) to detect leaf nodes.  If there is an
index on (lft, rgt) or just (lft), the speed is pretty good.



 DELETE FROM Tree


 WHERE lft = rgt -1


   AND <<other conditions>>;
Received on Mon Jul 28 2003 - 11:54:14 CDT












Original text of this message













  HOME |
  ASK QUESTION |
  ADD INFO |
  SEARCH |
  E-MAIL US