BIB-VERSION:: CS-TR-v2.0
          ID:: STAN//CS-TR-97-1583
       ENTRY:: January 09, 1997
ORGANIZATION:: Stanford University, Department of Computer Science
       TITLE:: Boolean Query Mapping Across Heterogeneous Information
               Sources (Extended Version)
        TYPE:: Technical Report
      AUTHOR:: Chang, Kevin Chen-Chuan
      AUTHOR:: Garcia-Molina, Hector
      AUTHOR:: Paepcke, Andreas
        DATE:: January 1997
       PAGES:: 17
    ABSTRACT:: Searching over heterogeneous information sources is difficult
               because of the non-uniform query languages. Our approach is
               to allow a user to compose Boolean queries in one rich
               front-end language. For each user query and target source, we
               transform the user query into a subsuming query that can be
               supported by the source but that may return extra documents.
               The results are then processed by a filter query to yield the
               correct final result. In this paper we introduce the
               architecture and associated algorithms for generating the
               supported subsuming queries and filters. We show that
               generated subsuming queries return a minimal number of
               documents; we also discuss how minimal cost filters can be
               obtained. We have implemented prototype versions of these
               algorithms and demonstrated them on heterogeneous Boolean
               systems.
       NOTES:: [Adminitrivia V1/Prg/19970109]
         END:: STAN//CS-TR-97-1583