Incomplete Information in Relational Databases
Journal of the ACM (JACM)
Finitely Specifiable Implicational Dependency Families
Journal of the ACM (JACM)
Update semantics of relational views
ACM Transactions on Database Systems (TODS)
Logic and Databases: A Deductive Approach
ACM Computing Surveys (CSUR)
Universality of data retrieval languages
POPL '79 Proceedings of the 6th ACM SIGACT-SIGPLAN symposium on Principles of programming languages
Horn clauses and the fixpoint query hierarchy
PODS '82 Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems
Partition semantics for incomplete information in relational databases
SIGMOD '88 Proceedings of the 1988 ACM SIGMOD international conference on Management of data
On deductive databases with incomplete information
ACM Transactions on Information Systems (TOIS)
A Probabilistic Framework for Vague Queries and Imprecise Information in Databases
VLDB '90 Proceedings of the 16th International Conference on Very Large Data Bases
VLDB '94 Proceedings of the 20th International Conference on Very Large Data Bases
Believe it or not: adding belief annotations to databases
Proceedings of the VLDB Endowment
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We study here automated deduction in databases in the presence of various types of inference rules of the form of Horn Clauses with Skolem functions. These inference rules are typical for databases with incomplete information. We demonstrate a number of results related to processing of conjunctive queries for different types of database intensions. In particular, we show that when a database intension is built from possibly cyclic inclusion dependencies and view definitions any conjunctive query can be translated to the an equivalent form which can be evaluated directly over the database extension (disregarding inference rules). We also demonstrate that the complexity of query processing significantly grows when we mix incomplete information with recursive rules. In particular, we demonstrate here that even the power of least fixpoint extension of first order logic may be not sufficient to process queries in the presence of incomplete data and recursive rules. The same is demonstrated in case disjunctive information is allowed in the database.