Re: Celko: short book on the nested sets model for trees.

From: --CELKO-- <71062.1056_at_compuserve.com>
Date: 8 Apr 2003 16:05:28 -0700
Message-ID: <c0d87ec0.0304081505.33c7741c@posting.google.com>

>> Do you know roughly when this is coming out in 03? <<

I am at an IBM show this week, but it is supposed to be back from a second text edit this coming week.

>> I understand that adjacency list model tree's can also be queried
using the WITH clause or the WITH RECURSIVE clause that is part of SQL99? <<

DB2 currently has the WITH clause, but not many other vendors seem to want to pick it up. And, yes, it can be used to hide a loop in an adjacency list model which will build the transitive closure.

>> Is this something that you'd be covering in your book, is this a
valid approach? <<

Yes, I mention it, but don't spend a lot of time on it since it is not yet popular.

I have mixed feeling about it; it is a SQL-99 Standard, but the FULL version of it is a nightmare with a dozen or so sub-clauses that are used to build the procedural code under the covers -- depth-first, breadth first, etc. search options for the hidden cursors, etc. Received on Tue Apr 08 2003 - 18:05:28 CDT