Evaluation of Signature Files as Set Access Facilities in OODBs

Yoshiharu Ishikawa (Doctoral Degree Program in Engineering, University of Tsukuba),
Hiroyuki Kitagawa (Institute of Information Sciences and Electronics, University of Tsukuba),
Nobuo Ohbo (Institute of Information Sciences and Electronics, University of Tsukuba),

PS file (10 pages, 341,784 bytes)


Object-oriented database systems (OODBs) need efficient support for manipulation of complex objects. In particular, support of queries involving evaluations of set predicates is often required in handling complex objects. In this paper, we propose a scheme to apply signature file techniques, which were originally invented for text retrieval, to the support of set value accesses, and quantitatively evaluate their potential capabilities. Two signature file organizations, the sequential signature file and the bit-sliced signature file, are considered and their performance is compared with that of the nested index for queries involving the set inclusion operator ($\subseteq$). We develop a detailed cost model and present analytical results clarifying their retrieval, storage, and update costs. Our analysis shows that the bit-sliced signature file is a very promising set access facility in OODBs.