Magic sets and other strange ways to implement logic programs (extended abstract)
PODS '86 Proceedings of the fifth ACM SIGACT-SIGMOD symposium on Principles of database systems
PODS '87 Proceedings of the sixth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Decidable optimization problems for database logic programs
STOC '88 Proceedings of the twentieth annual ACM symposium on Theory of computing
Semantical characterizations and complexity of equivalences in answer set programming
ACM Transactions on Computational Logic (TOCL)
Tractable Reasoning and Efficient Query Answering in Description Logics: The DL-Lite Family
Journal of Automated Reasoning
A general datalog-based framework for tractable query answering over ontologies
Proceedings of the twenty-eighth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Query rewriting and answering under constraints in data integration systems
IJCAI'03 Proceedings of the 18th international joint conference on Artificial intelligence
On rules with existential variables: Walking the decidability line
Artificial Intelligence
Ontological queries: Rewriting and optimization
ICDE '11 Proceedings of the 2011 IEEE 27th International Conference on Data Engineering
Ontological query answering via rewriting
ADBIS'11 Proceedings of the 15th international conference on Advances in databases and information systems
Walking the complexity lines for generalized guarded existential rules
IJCAI'11 Proceedings of the Twenty-Second international joint conference on Artificial Intelligence - Volume Volume Two
Extending decidable existential rules by joining acyclicity and guardedness
IJCAI'11 Proceedings of the Twenty-Second international joint conference on Artificial Intelligence - Volume Volume Two
Research summary: datalog-based data access
RR'12 Proceedings of the 6th international conference on Web Reasoning and Rule Systems
Hi-index | 0.00 |
In this paper we study query answering over ontologies expressed in Datalog+/---, i.e., datalog with existential variables in rule heads. Differently from previous proposals, we focus on subclasses of unions of conjunctive queries (UCQs), rather than on the whole class of UCQs. To identify subclasses of UCQs, we introduce the notion of conjunctive query pattern. Given a class of queries ${\mathcal Q}$ expressed by a conjunctive query pattern, we study decidability and complexity of answering queries in ${\mathcal Q}$ over a Datalog+/--- program. In particular, we define an algorithm that, given a Datalog+/--- program P and a class of queries ${\mathcal Q}$, is able to compute a simplified Datalog+/--- program P′ that is equivalent to P with respect to answering queries in ${\mathcal Q}$. We show that such an algorithm constitutes both a theoretical and a practical interesting tool for studying query answering over ontologies expressed in terms of Datalog+/--- rules.