1. A data base management system including a processor, a main memory (2), a large storage secondary memory (4), and a data structure contained in the main and secondary memories comprising a plurality of storage files (BNG pages 60, GLPAM pages 80, BNR pages 90) contained in the secondary memory, and a plurality of search trees (bit vectors 32, 36 and 73) hierarchically arranged in a plurality of search levels beginning with an initial tree (40) contained in the main memory, each tree containing ordered data defining parent nodes and terminal nodes of the tree, wherein a numerical representation of a path through parent nodes of the tree to reach any said terminal node of the tree defines a logical memory address of one of the storage files, and each terminal node of the search trees in a last search level defines a logical memory address of a terminating one of the storage files, and in which each of the storage files associated with the terminal nodes of the search trees except the trees in the last search level contains a link to one of the search trees in the next search level and each of the storage files associated with the terminal nodes of the search trees in the last search level contains stored information pertaining to a unique input search parameter, and the processor comprises program means for partitioning an input search parameter into a subparameter for each search level and for consecutively searching a linked one of the trees in each search level, starting with the initial tree, using a different one of the subparameters for each tree search until a terminating one of the storage files associated with the last search level is found.