First-order logic and automated theorem proving (2nd ed.)
First-order logic and automated theorem proving (2nd ed.)
On the content of materialized aggregate views
PODS '00 Proceedings of the nineteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Guarded fixed point logics and the monadic theory of countable trees
Theoretical Computer Science - Complexity and logic
Robbers, marshals, and guards: game theoretic and logical characterizations of hypertree width
Journal of Computer and System Sciences - Special issu on PODS 2001
The description logic handbook
Views and queries: determinacy and rewriting
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
The Semijoin Algebra and the Guarded Fragment
Journal of Logic, Language and Information
Determinacy and rewriting of conjunctive queries using views: a progress report
ICDT'07 Proceedings of the 11th international conference on Database Theory
Effective query rewriting with ontologies over DBoxes
IJCAI'09 Proceedings of the 21st international jont conference on Artifical intelligence
Views and queries: Determinacy and rewriting
ACM Transactions on Database Systems (TODS)
Determinacy and query rewriting for conjunctive queries and views
Theoretical Computer Science
Conjunctive queries determinacy and rewriting
Proceedings of the 14th International Conference on Database Theory
Determinacy and rewriting of conjunctive queries over unary database schemas
Proceedings of the 2011 ACM Symposium on Applied Computing
View determinacy for preserving selected information in data transformations
Information Systems
PODS '12 Proceedings of the 31st symposium on Principles of Database Systems
Exact query reformulation with first-order ontologies and databases
JELIA'12 Proceedings of the 13th European conference on Logics in Artificial Intelligence
Access patterns and integrity constraints revisited
Proceedings of the 16th International Conference on Database Theory
Beth definability in expressive description logics
Journal of Artificial Intelligence Research
Exact query reformulation over databases with first-order and description logics ontologies
Journal of Artificial Intelligence Research
| Hi-index | 0.01 |
A query Q is determined by a set of views V if, whenever V (I1) = V (I2) for two database instances I1, I2 then also Q(I1) = Q(I2). Does this imply that Q can be rewritten as a query Q0 that only uses the views V?. For first-order (FO) queries and view definitions over possibly infinite databases, the answer is yes, as follows from old results of Beth and Craig. We say that FO is complete for FO-to-FO rewritings. However, Nash, Segoufin and Vianu (2007) prove that if the query and the view definitions are given by conjunctive queries, then it might not be possible to formulate Q' as a conjunctive query. In other words, CQ is not complete for CQ-to-CQ rewritings. Here we consider queries and view definitions in the packed fragment (PF) of first-order logic. This is a generalization of the guarded fragment, a fragment of particular interest to database theory. Gottlob et.al. 2002 show that the guarded conjunctive queries are exactly the acyclic queries. Leinders et.al. 2005 characterize the entire guarded fragment by the semijoin algebra. We show that for both finite and unrestricted databases, PF is complete for PF-to-PF rewritings. The same holds for packed (unions of) conjunctive queries. In both cases, we provide algorithms for testing whether a query is determined by a set of views, and for actually rewriting Q to Q'. To compare: these problems are undecidable for full FO, and still open for conjunctive queries.