Incomplete Information in Relational Databases
Journal of the ACM (JACM)
Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
Incomplete object—a data model for design and planning applications
SIGMOD '91 Proceedings of the 1991 ACM SIGMOD international conference on Management of data
Complexity tailored design: a new design methodology for databases with incomplete information
Journal of Computer and System Sciences - Special issue on selected papers presented at the 24th annual ACM symposium on the theory of computing (STOC '92)
A semantics for reasoning consistently in the presence of inconsistency
Artificial Intelligence
Null inclusion dependencies in relational databases
Information and Computation
Consistent query answers in inconsistent databases
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Database relations with null values
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
Reasoning in Inconsistent Knowledge Bases
IEEE Transactions on Knowledge and Data Engineering
Flexible Relation: An Approach for Integrating Data from Multiple, Possibly Inconsistent Databases
ICDE '95 Proceedings of the Eleventh International Conference on Data Engineering
A Logic Programming Approach to the Integration, Repairing and Querying of Inconsistent Databases
Proceedings of the 17th International Conference on Logic Programming
Data Integration under Integrity Constraints
CAiSE '02 Proceedings of the 14th International Conference on Advanced Information Systems Engineering
Query Answering in Information Systems with Integrity Constraints
Proceedings of the IFIP TC11 Working Group 11.5, First Working Conference on Integrity and Internal Control in Information Systems: Increasing the confidence in Information Systems
Integrating data from possibly inconsistent databases
COOPIS '96 Proceedings of the First IFCIS International Conference on Cooperative Information Systems
The complexity of relational query languages (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
A Logical Framework for Querying and Repairing Inconsistent Databases
IEEE Transactions on Knowledge and Data Engineering
A cost-based model and effective heuristic for repairing constraints by value modification
Proceedings of the 2005 ACM SIGMOD international conference on Management of data
Data exchange: semantics and query answering
Theoretical Computer Science - Database theory
Database repairing using updates
ACM Transactions on Database Systems (TODS)
Consistent query answering in databases
ACM SIGMOD Record
Minimal-change integrity maintenance using tuple deletions
Information and Computation
Querying inconsistent databases
LPAR'00 Proceedings of the 7th international conference on Logic for programming and automated reasoning
Consistent query answering: five easy pieces
ICDT'07 Proceedings of the 11th international conference on Database Theory
Semantically correct query answers in the presence of null values
EDBT'06 Proceedings of the 2006 international conference on Current Trends in Database Technology
Design by example for SQL table definitions with functional dependencies
The VLDB Journal — The International Journal on Very Large Data Bases
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This paper addresses the problem of efficiently computing consistent answers to queries over relational databases which may be inconsistent with respect to functional dependencies and foreign key constraints. Since consistent query answers over inconsistent databases are obtained from repaired databases, we first present a repair strategy. More specifically, in this paper we consider particular sets of functional dependencies, called canonical, and a repair strategy whereby only tuple updates and insertions are allowed in order to restore consistency: if foreign key constraints are violated, new tuples (possibly containing null values) are inserted into the database, whereas if functional dependency violations occur, tuple updates (possibly introducing unknown values, i.e. special symbols which can take values from a limited set of constants of the source database) are performed. Therefore, we propose a semantics of constraint satisfaction for incomplete databases containing null and unknown values since the repair process can lead to such databases. The proposed approach allows us to obtain a unique (incomplete) repaired database which may be computed in polynomial time. Drawing on the results on the complexity of querying incomplete databases containing OR-objects, we identify classes of constraints for which the consistent answers to particular classes of conjunctive queries can be computed in polynomial time.