Abstract: The minimum value or the maximum value of the index keys of a coupled node tree of a processing source is determined, and the index keys are successively deleted until the index key that is to be the splitting point is reached, the deleted index keys being inserted into the coupled node tree of the processing target, thereby splitting the coupled node tree. Deletion processing is done of one coupled node tree, taking as the processing source in the above-noted splitting method, and insertion processing is done of the other, taken as the processing target, thereby conjoining the coupled node trees.

Abstract: Bit string searching apparatus using a coupled node tree with a root node and a node pair stored in adjacent areas that is formed by a branch node and a leaf node, branch nodes, or leaf nodes; the branch node including a discrimination bit position in the search key and information indicating a position of a primary node that is one node of a node pair; the leaf node including an index key formed by a bit string; from the root node of an arbitrary subtree of the coupled node tree, linking is repeated based on the search key's bit value at the discrimination bit position and information indicating a position of a primary node until a leaf node is reached; an index key stored in the leaf node is obtained as a search result key of the subtree by means of the search key.

Abstract: A database management system includes an object conversion unit converting each of a plurality of natural objects and each of a plurality of object IDs of consecutive data according to a predetermined rule in a unique relationship and a bidirectional manner; and a database storing tables of a hierarchical structure including the object IDs converted by said object conversion unit as a permanent object holding data during a period. The tables of the hierarchical structure have a data structure formed by connecting a lower table and another lower table through at least one upper table on a chain and in a bidirectional manner.