ABSTRACT
We study the problem of query containment of (unions of) conjunctive queries over annotated databases. Annotations are typically attached to tuples and represent metadata such as probability, multiplicity, comments, or provenance. It is usually assumed that annotations are drawn from a commutative semiring. Such databases pose new challenges in query optimization, since many related fundamental tasks, such as query containment, have to be reconsidered in the presence of propagation of annotations.
We axiomatize several classes of semirings for each of which containment of conjunctive queries is equivalent to existence of a particular type of homomorphism. For each of these types we also specify all semirings for which existence of a corresponding homomorphism is a sufficient (or necessary) condition for the containment. We exploit these techniques to develop new decision procedures for containment of unions of conjunctive queries and axiomatize corresponding classes of semirings. This generalizes previous approaches and allows us to improve known complexity bounds.
- F.N. Afrati, M. Damigos, M. Gergatsoulis. Query contain- ment under bag and bag-set semantics. IPL 110(10), 2010. Google Scholar
Digital Library
- P. Buneman, J. Cheney, W.C. Tan, S. Vansummeren. Curated databases. PODS 2008, 1--12. Google Scholar
Digital Library
- P. Buneman, S. Khanna, W.C. Tan. Why and Where: a characterization of data provenance. ICDT 2001, 316--330. Google Scholar
Digital Library
- P. Buneman, E.V. Kostylev. Annotation Algebras for RDFS. SWPM 2010. CEUR Workshop Proc.Google Scholar
- A.K. Chandra, P.M. Merlin. Optimal implementation of conjunctive queries in relational data bases. STOC 1977. Google Scholar
Digital Library
- S. Chaudhuri, M.Y. Vardi. Optimization of real conjunctive queries. PODS 1993, 59--70. Google Scholar
Digital Library
- R. Chirkova. Equivalence and minimization of conjunctive queries under combined semantics. ICDT 2012. Google Scholar
Digital Library
- S. Cohen, W. Nutt, Y. Sagiv. Deciding equivalences among conjunctive aggregate queries. JACM series 54(2), 2007. Google Scholar
Digital Library
- Y. Cui, J. Widom, J.L. Wiener. Tracing the lineage of view data in a warehousing environment. ACM,ToDS 25(2), 179--227, 2000. Google Scholar
Digital Library
- A. Das Sarma, M. Theobald, J. Widom. Exploiting lineage for confidence computation in uncertain and probabilistic databases. ICDE 2008, 1023--1032. Google Scholar
Digital Library
- R. Fagin, P.G. Kolaitis, L. Popa, W.C. Tan. Quasi-inverses of schema mappings. ACM,ToDS 33(2), 2008. Google Scholar
Digital Library
- N. Fuhr, T. Rölleke. A probabilistic relational algebra for the integration of information retrieval and database systems. ACM,ToIS 15(1), 32--66, 1997. Google Scholar
Digital Library
- G. Grahne, N. Spyratos, D. Stamate. Semantics and containment of queries with internal and external conjunctions. ICDT 1997, LNCS 1186, 71--82. Google Scholar
Digital Library
- T.J. Green. Containment of conjunctive queries on annotated relations. Th. Comp. Syst. 49(2), 429--459, 2011. Google Scholar
Digital Library
- T.J. Green, G. Karvounarakis, V. Tannen. Provenance semirings. PODS 2007, 31--40. Google Scholar
Digital Library
- T. Imieli'nski, W. Lipski, Jr. Incomplete information in relational databases. JACM '31(4), 761--791, 1984. Google Scholar
Digital Library
- Y.E. Ioannidis, R. Ramakrishnan. Containment of conjunctive queries: beyond relations as sets. ACM,ToDS 20(3), 1995. Google Scholar
Digital Library
- T.S. Jayram, P.G. Kolaitis, E. Vee. The containment problem for phreal conjunctive queries with inequalities. PODS 2006. Google Scholar
Digital Library
- D. Olteanu, J. Závodný. Factorised representations of query results: size bounds and readability. ICDT 2012. Google Scholar
Digital Library
- Y. Sagiv, M. Yannakakis. Equivalences among relational expressions with the union and difference operators. JACM 27(4), 633--655, 1980. Google Scholar
Digital Library
- E. Zimányi. Query evaluation in probabilistic relational databases. TCS 171(1--2), 179--219, 1997. Google Scholar
Digital Library
- A. Zimmermann, N. Lopes, A. Polleres, U. Straccia. A general framework for representing, reasoning and querying with annotated Semantic Web data. Web Semantics. In press. Google Scholar
Digital Library
Index Terms
Classification of annotation semirings over query containment
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