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Im not sure how you have implemented the drop/delete node, but it seems that if i would drop a node with 1000 descendants it would cost me 1000 selects, 1000 deletes and 1000 updates. This is is usually done with two statements, one delete and one update. If you have this tree and you would like to drop node C and it's descendants: | 1 A 12 /-----------------+-----------------\ | | | 2 B 3 4 C 9 10 D 11 /-----------\ | | 5 E 6 7 F 8 DELETE FROM tree WHERE lft BETWEEN :lft AND :rgt :lft = 4 :rgt = 9 UPDATE tree SET lft = CASE WHEN lft > :lft THEN lft - :gaps ELSE lft END, rgt = CASE WHEN rgt > :rgt THEN rgt - :gaps ELSE rgt END WHERE rgt > :lft :gaps = 9 - 4 + 1 (:rgt - :lft + 1) :lft = 4 :rgt = 9 And the result: | 1 A 6 /-----------\ | | 2 B 3 4 D 5 The Nested Set algorithm is one of my favorites, it's very efficient and portable. It can handle large trees with out problems. In reply to Re: RFC: DBIx::Tree::NestedSet
by Hansen
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