A Proof Procedure for Data Dependencies
Journal of the ACM (JACM)
Efficient optimization of a class of relational expressions
ACM Transactions on Database Systems (TODS)
Data integration: a theoretical perspective
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Testing implications of data dependencies
SIGMOD '79 Proceedings of the 1979 ACM SIGMOD international conference on Management of data
Testing containment of conjunctive queries under functional and inclusion dependencies
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
Reformulation of XML Queries and Constraints
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Answering queries using views: A survey
The VLDB Journal — The International Journal on Very Large Data Bases
Data exchange: semantics and query answering
Theoretical Computer Science - Database theory
Query reformulation with constraints
ACM SIGMOD Record
ACM Transactions on Database Systems (TODS)
QUIST: a system for semantic query optimization in relational databases
VLDB '81 Proceedings of the seventh international conference on Very Large Data Bases - Volume 7
Efficient core computation in data exchange
Journal of the ACM (JACM)
Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Datalog±: a unified approach to ontologies and integrity constraints
Proceedings of the 12th International Conference on Database Theory
SPROUT: Lazy vs. Eager Query Plans for Tuple-Independent Probabilistic Databases
ICDE '09 Proceedings of the 2009 IEEE International Conference on Data Engineering
Foundations of SPARQL query optimization
Proceedings of the 13th International Conference on Database Theory
Static analysis of schema-mappings ensuring oblivious termination
Proceedings of the 13th International Conference on Database Theory
Semantic query optimization in the presence of types
Proceedings of the twenty-ninth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
SecureBlox: customizable secure distributed data processing
Proceedings of the 2010 ACM SIGMOD International Conference on Management of data
On the termination of the chase algorithm
RR'10 Proceedings of the Fourth international conference on Web reasoning and rule systems
Chase termination: a constraints rewriting approach
Proceedings of the VLDB Endowment
Relaxed notions of schema mapping equivalence revisited
Proceedings of the 14th International Conference on Database Theory
ACM Transactions on Database Systems (TODS)
Ontological query answering with existential rules
RR'11 Proceedings of the 5th international conference on Web reasoning and rule systems
Towards farsighted dependencies for existential rules
RR'11 Proceedings of the 5th international conference on Web reasoning and rule systems
ChaseT: a tool for checking chase termination
SUM'11 Proceedings of the 5th international conference on Scalable uncertainty management
Computing universal models under guarded TGDs
Proceedings of the 15th International Conference on Database Theory
LogicBlox, platform and language: a tutorial
Datalog 2.0'12 Proceedings of the Second international conference on Datalog in Academia and Industry
Disjunctive datalog with existential quantifiers: Semantics, decidability, and complexity issues
Theory and Practice of Logic Programming
Flag & check: data access with monadically defined queries
Proceedings of the 32nd symposium on Principles of database systems
Semantic query optimization in the presence of types
Journal of Computer and System Sciences
Acyclicity notions for existential rules and their application to query answering in ontologies
Journal of Artificial Intelligence Research
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We study the termination problem of the chase algorithm, a central tool in various database problems such as the constraint implication problem, Conjunctive Query optimization, rewriting queries using views, data exchange, and data integration. The basic idea of the chase is, given a database instance and a set of constraints as input, to fix constraint violations in the database instance. It is well-known that, for an arbitrary set of constraints, the chase does not necessarily terminate (in general, it is even undecidable if it does or not). Addressing this issue, we review the limitations of existing sufficient termination conditions for the chase and develop new techniques that allow us to establish weaker sufficient conditions. In particular, we introduce two novel termination conditions called safety and inductive restriction, and use them to define the so-called T-hierarchy of termination conditions. We then study the interrelations of our termination conditions with previous conditions and the complexity of checking our conditions. This analysis leads to an algorithm that checks membership in a level of the T-hierarchy and accounts for the complexity of termination conditions. As another contribution, we study the problem of data-dependent chase termination and present sufficient termination conditions w.r.t. fixed instances. They might guarantee termination although the chase does not terminate in the general case. As an application of our techniques beyond those already mentioned, we transfer our results into the field of query answering over knowledge bases where the chase on the underlying database may not terminate, making existing algorithms applicable to broader classes of constraints.