nested set: algorithm for testing the integrity

I'm looking for a algorithm which checks if a nested set with many
nodes and levels is correct.

I know the pear class and I have read a few tutorials, maybe there is
a mathematical solution for this test?

thx.

alexander.buze@googlemail.com wrote:
> I'm looking for a algorithm which checks if a nested set with many
> nodes and levels is correct.
>
> I know the pear class and I have read a few tutorials, maybe there is
> a mathematical solution for this test?
>
> thx.
>

i think you're talking php.
check http://www.phpclasses.org


--
lark -- hamzee@sbcdeglobalspam.net
To reply to me directly, delete "despam".

>> algorithm which checks if a nested set with many nodes and levels is correct. <<

1) Buy a copy of TREES & HIERARCHIES IN SQL
2) Create a view called LftRgt which has all the lft and rgt values
unioned in it
3) No gaps in the numbering: (SELECT MAX(rgt) FROM Tree) = (SELECT
COUNT(*) FROM LftRgt)
4) No duplicated values: NOT EXISTS (SELECT seq FROM LftRgt GROUP BY
seq HAVING COUNT(*) > 1)
5) No overlapping (lft, rgt) pairs: an exercise for the reader