Patent ID: 7343381
Filing Date: 2008-03-11
Classification: G06F,Y10S

Abstract:
1. An index structure for metadata divided into fragments, the index structure contained in a computer readable storage medium and comprising: a key index list section comprising a list of multi-keys, each multi-key corresponding to a combination of fields of the metadata used simultaneously to locate and extract a fragment of metadata; a key index section; and a sub-key index section, wherein for a multi-key of the key index list: the sub-key index section comprises ranges of values of the multi-key and identification information on ones of the fragments of the metadata corresponding to the values of the multi-key, and the key index section comprises representative key values representing the respective ranges of values of the multi-key, wherein with respect to comparison of the values of a multi-key in size, the multi-key comprises fields (k1, k2, k3 . . . kn) of the metadata which are prioritized (k1>k2>k3> . . . Kn), and the combined fields are compared in sequence, starting from a first field having a highest order of priority, wherein the values are compared on an arithmetic basis where the values of the multi-key are numerical or ranked in lexicographical order where the values of the multi-key are alphabetical, wherein for two multi-key values, (a1, a2, . . . an) and (b1, b2, . . . , bn): (a1, a2, . . . , an) is larger than (b1, b2, . . . , bn) if and only if there exists an integer i (0≦i≦n−1) such that for every j (0≦i≦n−1), aj=bj and ai>bi; (a1, a2, . . . , an) is smaller than (b1, b2, . . . , bn) if and only if there exists an integer i (0≦i≦n−1) such that for every j (0≦i≦n−1), aj=bj and ai<bi; and (a1, a2, . . . , an) is equal to (b1, b2, . . . , bn) if and only if for every i (0≦i≦n−1), ai=bi.