Incomplete Information in Relational Databases
Journal of the ACM (JACM)
Relational queries computable in polynomial time
Information and Control
Does co-NP have short interactive proofs?
Information Processing Letters
On the representation and querying of sets of possible worlds
SIGMOD '87 Proceedings of the 1987 ACM SIGMOD international conference on Management of data
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
The complexity of relational query languages (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
Optimal implementation of conjunctive queries in relational data bases
STOC '77 Proceedings of the ninth annual ACM symposium on Theory of computing
Graph isomorphism and self-complementary graphs
ACM SIGACT News
Incomplete object—a data model for design and planning applications
SIGMOD '91 Proceedings of the 1991 ACM SIGMOD international conference on Management of data
Statistical inference of unknown attribute values in databases
CIKM '93 Proceedings of the second international conference on Information and knowledge management
Speculative query evaluation over databases of plans
CIKM '93 Proceedings of the second international conference on Information and knowledge management
Data mining for design and manufacturing
On the complexity of data disjunctions
Theoretical Computer Science - Complexity and logic
Searching a minimal semantically-equivalent subset of a set of partial values
The VLDB Journal — The International Journal on Very Large Data Bases
Using Constraints for Efficient Query Processing in Nondeterministic Databases
IEEE Transactions on Knowledge and Data Engineering
An Exploration of Relationships Among Exclusive Disjunctive Data
IEEE Transactions on Knowledge and Data Engineering
Evaluating Aggregate Operations Over Imprecise Data
IEEE Transactions on Knowledge and Data Engineering
Disjunctive Logic Programming: A Survey and Assessment
Computational Logic: Logic Programming and Beyond, Essays in Honour of Robert A. Kowalski, Part I
Polynomial Time Queries over Inconsistent Databases
SUM '08 Proceedings of the 2nd international conference on Scalable Uncertainty Management
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If ground disjunctive facts are admitted into a database the data complexity of conjunctive queries grows from PTIME into CoNP with some simple examples of CoNP-Complete conjunctive queries. A natural question which arises in this context is whether it is possible to syntactically characterize those queries which are “bad” (i.e. CoNP-Complete) from those that are “good” (i.e. with PTIME data complexity) given a predefined 'pattern” of disjunctions in the database. In this paper, we study the data complexity of conjunctive queries. We give a complete syntactic characterization of CoNP-Complete conjunctive queries for a class of disjunctive databases called OR-Databases. Our results can be used in complexity tailored design where design decisions are motivated by complexity of query processing. Also, we establish that a similar complete syntactic characterization for disjunctive queries, with negation allowed only on base predicates, would answer the open problem “Does Graph Isomorphism belong to PTIME or is it NP-Complete?”.