Query mapping and transformation techniques for problem solving with multiple knowledge servers

TitleQuery mapping and transformation techniques for problem solving with multiple knowledge servers
Publication TypeJournal Articles
Year of Publication1993
AuthorsRaschid L, Chang Y, Dorr BJ
JournalProceedings of the Second International Conference on Information and Knowledge Management (CIKM-93)
Date Published1993///
Abstract

This paper describes a technique for infor-mation mediation when multiple heterogeneous knowl-
edge and data servers are to be accessed during query
processing. One problem is building an intelligent in-
terface between each knowledge server (KS) and its
processor (KP); and the second is to provide interoper-
ability among multiple KP/KS so that a query may be
answered using information from multiple sources. We
present example scenarios which highlight these prob-
lems and then outline query mapping and transforma-
tion techniques that are applicable. The techniques
for solving the interoperability problems involve rep-
resentations in some canonical form. This includes a
canonical representation (CR) corresponding to each
KP/KS pair and a merged CR (MCR) to represent the
mapping among the CRs. The MCR and CRs include
relevant information obtained from a source query, and
heterogeneous mapping (het-map) information, for all
possible mappings among the multiple servers. The
knowledge in the canonical form must be represented
so that it can be easily accessed during query transfor-
mation. We use an example of translating queries from
an object schema to a relational schema to illustrate
typical knowledge that must be represented in some
canonical form. We use a high level logical language,
F-logic, to represent the heterogeneous mapping (het-
map) and query transformation information as a set
of declarative rules, in the canonical form.