Patent ID: 7177854
Filing Date: 2007-02-13
Classification: G06F,Y10S

Abstract:
1. Method for processing a data cube for range-sum queries which includes a prefixed-sum cube to store the cumulative sum of data and a dynamic update cube using an multidimensional index structure called Δ-tree to store the updated values of the data cube comprising: storing only the changed information of the cell in the data cube into the Δ-tree, which constructed by the same process as a R*-tree, in which initially, the Δ-tree has only a directory node called root node, and whenever the data cube cell is updated, the difference Δ between new and old values of the data cube cell and its spatial position information are stored in the Δ-tree, instead of updating directly to the prefixed-sum cube, wherein the directory node contains (L with where f(k 1 ,k 2 , . . . k d ) is the value of an update position (k 1 , k 2 , . . . , k d ) in MBR i with 1 ≦k j ≦n j , and n j is the number of partitions of the j-th dimension of MBR i , and the data node is at level 0 and it contains (D 1 , D 2 , . . . , D n ), where D i is the tuple about i-th data entry and has the form (P i , Δ i ), with P i being the position index and Δ i being the difference between the changed cell; and managing the Δ-tree to improve the update speed of the data cube.