| 摘要 |
A method and apparatus for storing and retrieving multi-dimensional data in which a multi-level data structure is defined wherein one level contains those dimensions chosen by the user to result in dense data and the other level contains the remaining sparse data combinations. The dense dimensions specified in any given case are used to determine the basic block size used to store information. The remaining sparse dimensions are used to create the upper level structure which is used to point to the block which contains the desired information. Depending upon the sparseness of the data, different types of upper level structure may be used. Both the variable data block size and the choice of pointer structure may be used to balance the memory required against the speed of retrieval. Once the data structure is created, the data in the data blocks, and the pointers in one type of upper level pointer structure, may be retrieved by simple calculation of the offset of the desired cell in memory rather than requiring a search. |
