Hash-based system and method with primary and secondary hash functions for rapidly identifying the existence and location of an item in a file

摘要

A system and method for rapidly identifying the existence and location of an item in a file using an improved hash table architecture. A hash table is constructed having a plurality of hash buckets, each identified by a primary hash key. Each hash entry in each hash bucket contains a pointer to a record in a master file, as well as a secondary hash key independent of the primary hash key. A search for a particular item is performed by identifying the appropriate hash bucket by obtaining a primary hash key for the search term. Individual hash entries within the hash bucket are checked for matches by comparing the stored secondary keys with the secondary key for the search term. Potentially matching records can be identified or ruled out without necessitating repeated reads of the master file. The improved hash table system and method is employed in a contextual text searching application for determining the intersection of a text search with a hierarchical categorization scheme.