Signature Files: An Integrated Access Method for Formatted and Unformatted Databases

----*------.----..-...-.-...-.*.-*-....-.-*.----..----.-*...-...-...---.----.--... ".. The signature file approach is one of the most powerful information storage and retrieval techniques which is used for finding the data objects that are relevant to the user queries. The main idea of all signature based schemes is to reflect the essence of the data items into bit patter& (descriptors or signatures) and store them in a separate file which acts as a filter to eliminate the non aualifvine data items for an information reauest. It pro;ides an integrated access method for both formattid and &formatted databases. A comp&ative overview and discussion of the proposed signatnre generation methods and the major signature file organization schemes are presented. Applications of the signature techniques to formatted and unformatted databases, single and multiterm query cases, serial and paratlei architecture. static and dynamic environments are provided with a special emphasis on the multimedia databases where the pioneering prototype systems using signatnres yield highly encouraging results.