Linked Lists in Oracle Tables

If I'm storing a hierrachy in an Oracle table, is there any benefit in making the records "doubly-linked" (i.e. each having a "parent" and a "child" reference) rather than simply having a "singly-linked" list
(i.e. just a "parent" reference)?

In order to find all the offspring of a record in a singly-linked system, I have (or the system has) to examine every record to see if it has me as a "parent". Then repeat this step for all my 1st generation children, etc., until I have a complete list.

In the doubly-linked version, although I can quickly identify the children (have a foreign key to them) I have (or the system has) still to examine every record to see if it is the right one. Then repeat for all the 1sr generation children found ...

On the face of it, the doubly-linked version doesn't seem to save much
(although it is able to stop searching once it has found the matching
record).

Is that really as good as it gets? Doesn't Oracle efficientize this somehow? Is there no real concept of "pointers" that can take you directly to another referenced record, without having to check all records against the key to find the match? Received on Thu Apr 10 2003 - 22:19:18 CEST