Re: Tree structures in an RDBMS

> The following is my current challenge:
> - ability for branch queries forward as well as backward: i.e. given
> a node X, I need to get all nodes and leaves that are below X, given
> a node Y, I need all nodes in the path from the root down to Y.
> - extensibility: there must not be a hard limit on the number of nodes
> or the number of tree levels, the tree must accept addition of new
> nodes at any position
> - reorderability: from time to time branches will need to get reordered
> within the tree e.g. move a specific branch from level 4 below a node Y
> to level 12 below node Z.
>
> The tree is supposed to have about 15 levels with a mean of 3 child nodes
> arising from each parent. This lets me end up at the calculation of
> Sum(k=1;15;3^k)=21*10^6 nodes to store in my representation.
> Most queries will be directed "forward", i.e. from a specific node X down to
> the leaves, and will typically start 3 levels above the mean leaf level for
> that branch.

XDb (www.xdb1.com) is well suited for the above requirements; unfortunately, it is a RAM-resident oodb. Received on Fri Nov 30 2001 - 00:07:44 CET