Designing Views to Efficiently Answer Real SQL Queries
Foto Afrati, Rada Chirkova, Manolis Gergatsoulis, Vassia Pavlaki
The problem of optimizing queries in the presence of materialized views and the
related view-design problem have recently attracted a lot of attention.
Significant research results have been
reported, and materialized views are increasingly used in query
evaluation in commercial data-management systems. At the same
time, most results in the literature assume set-theoretic
semantics, whereas SQL queries have bag-theoretic semantics
(duplicates are not eliminated unless explicitly requested). This
paper presents results on selecting views to answer queries in
relational databases under set, bag, and bag-set semantics. The
results can be used under each of the three assumptions, to find
sound and complete algorithms for designing views and rewriting
Data integration, query transformation, database theory.