excellent article. But i got a question. I hav a tree structure which i want to store in a DB. The structure is not fixed and can change, ie, nodes can b added, deleted or renamed.

Using your article, i find that i can navigate and extract data from such a structure very effeciently. But how do i deal with inserting and deleting the nodes into the DB table?

I am using this from a C# application and my DB is MySQL.

My tree structure concerns a document archive that is full of old documents that are old enough to get damaged if accessed repeatedly and so need to be scanned and put into the DB. The arrangement of the documents follow a tree structure i.e.:

Archive root>>Room no>>Cabin no>>Drawer no>>category

the first 3 levels i.e. room, cabin and drawer remain constant but the category can have many sub levels. Files can b stored directly under category level as well as under any sub level of category, and so i am using a tree structure to store this location info. What i am planning to do is to create the tree with the first 3 levels and then allow the client to put up further nodes as and when they need. Then they can upload scanned documents to the appropriate places.

The file upload to any level is OK as far as that level/sub category is already defined and stored properly in the DB and can be accessed properly. To make navigation and search of documents from this tree effective and fast i wanted to first of all speed up the tree navigation itself and thus came upon your article. The navigation using your method will be fast even if there are too many sub-levels and files, but how do I manage the insert and delete of the various sub-levels when using your method? Do I need to calculate the Left and Right bower every time a node is inserted or deleted?

I want to do this right from the beginning because i know the amount of data they have is humongous. The DB will slow down because of this and thus the app i am making would slow down too...