<algorithm> (B-tree) An optimisation of a binary tree which aims to keep equal numbers of items on each side of each node so as to minimise the maximum path from the root to any leaf node. As items are inserted and deleted, the B-tree is restructured to keep the nodes balanced and the search paths uniform. Such an algorithm is appropriate where the overheads of the reorganisation on update are outweighed by the benefits of faster search.
A B+-tree (as used by IBM's VSAM) is a B-tree where the leaves are also linked sequentially, thus allowing both fast random access and sequential access to data.
(15 Apr 1996)