B+TREE ON-DISK RECORDING METHOD AND PROGRAM

PROBLEM TO BE SOLVED: To effectively utilize a space in a single disk block when data amount of a single inner node is smaller with respect to the space in a single disk block.SOLUTION: The recording method creates a B+tree index from an integer sequence which is input through an integer sequence input device, and allots plural internal nodes to a single disk block to write the same in a storing unit of the B+tree index. The B+tree index is divided according to the height of the internal node of the B+tree index and each of the internal nodes belonging to an identical height i is decomposed into plural sets of j. A piece of information necessary for processing database and a piece of offset information for plural mini disk blocks are stored at the head of the disk block as a header. A piece of information necessary for search is written in the header of a k-th mini disk block in the disk block. The information of a set of the k-th internal nodes is stored in the k-th mini disk block.