Linear hashing with partial expansions

摘要: A new method for organising dynamic files is presented and its performance analysed. The scheme a generalization of W. Litwin's linear (virtual) hashing. amount storage space allocated to the file grows shrinks in simple fashion according number records actually stored file. utilisation controlled constantly kept equal threshold selected by user. Because no index or other form access table used, retrieval record requires only one most cases. analysis reveals that an average search length range 1.1 - 1.2 accesses can easily be achieved, even utilisations as high 85-90 per cent.