Betternestedset talk - Oct 2006 - check consistency

Here is the sql to check some consistency in a tree:

# check each lft and rgt values are unique
SELECT * FROM mytree m1, mytree m2 WHERE (m1.lft=m2.lft OR 
m1.rgt=m2.rgt OR m1.lft=m2.rgt) AND m1.id<>m2.id;

# check boundaries : 1..maxr, maxr = 2*count(leaves in tree)
SELECT * FROM mytree m WHERE (m.lft NOT BETWEEN 1 AND 30) OR (m.rgt NOT 
BETWEEN 1 AND 30);


Jean-Christophe Michel
--
symetrie.com

Better Nested Set for rails:
http://opensource.symetrie.com/trac/better_nested_set