1. A method of performing a retrieval operation in a database comprising a tree of nodes, wherein the tree of nodes comprises a root node which is connected to two or more branches originating at the root node, wherein each branch terminates at a node, wherein each node other than the root node may be a non-terminal node or a leaf node, wherein each non-terminal node is connected to two or more branches originating at the non-terminal node and terminating at a node, wherein each leaf node comprises one or more data records of the database, wherein a test associated with each non-terminal node defines a partition of data records based upon one of entropy/adjacency partition assignment and data clustering using multivariate statistical analysis, wherein a current node is initially set to the root node, said method comprising the steps of: (a) receiving input of a search request providing a retrieval operation and information necessary to perform the retrieval operation; (b) performing the test associated with a current node responsive to the search request, said test resulting in identification of zero or more distal nodes connected to the current node, wherein said identified distal nodes can, according to the test, contain the data record; (c) repeating step (b) using an untested distal node which is a non-terminal node as the current node; and (d) performing the retrieval operation on each identified node that is a leaf node.