Incomplete Information in Relational Databases
Journal of the ACM (JACM)
On the representation and querying of sets of possible worlds
SIGMOD '87 Proceedings of the 1987 ACM SIGMOD international conference on Management of data
POPL '87 Proceedings of the 14th ACM SIGACT-SIGPLAN symposium on Principles of programming languages
A model-based approach to updating databases with incomplete information
ACM Transactions on Database Systems (TODS)
Null values in definite programs
Proceedings of the 1990 North American conference on Logic programming
Constraint query languages (preliminary report)
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
PPCP '94 Proceedings of the Second International Workshop on Principles and Practice of Constraint Programming
Update semantics for incomplete databases
VLDB '85 Proceedings of the 11th international conference on Very Large Data Bases - Volume 11
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It is the aim of the research described in this paper is to to extend the work to deductive databases by proposing a theory of indefinite deductive constraint databases (IDCDs). This model provides a useful and natural representation of partial and infinite information. As a result of basing our representation of incomplete information on constraints, we can easily extend our model in order to enable the representation of temporal and/or spatial data by defining the domain of variables over which constraints can be defined to either be the temporal or spatial domain or by using, for example, linear arithmetic constraints to represent these domains. We describe how the syntax of the deductive database model can be enhanced with global conditions on incompletely specified constants to naturally represent partial information and provide a full declarative, fixpoint and procedural semantics for the language defined. We discuss an as yet unexplored problem with respect to constraint databases - that of updating and maintaining a consistent set of data in the presense of global conditions on incomplete information.