On knowledge base management systems: integrating artificial intelligence and d atabase technologies
On knowledge base management systems: integrating artificial intelligence and d atabase technologies
Independent and separable database schemes
SIAM Journal on Computing
Foundations of deductive databases and logic
Foundations of deductive databases and logic
Update semantics of relational views
ACM Transactions on Database Systems (TODS)
The theory of joins in relational databases
ACM Transactions on Database Systems (TODS)
Independent components of relations
ACM Transactions on Database Systems (TODS)
Equality and Domain Closure in First-Order Databases
Journal of the ACM (JACM)
A Complete Axiomatization of Full Join Dependencies
Journal of the ACM (JACM)
Horn clauses and database dependencies
Journal of the ACM (JACM)
On the Desirability of Acyclic Database Schemes
Journal of the ACM (JACM)
POPL '86 Proceedings of the 13th ACM SIGACT-SIGPLAN symposium on Principles of programming languages
Canonical view update support through boolean algebras of components
PODS '84 Proceedings of the 3rd ACM SIGACT-SIGMOD symposium on Principles of database systems
Algebraic aspects of relational database decomposition
PODS '83 Proceedings of the 2nd ACM SIGACT-SIGMOD symposium on Principles of database systems
GAMMA - A High Performance Dataflow Database Machine
VLDB '86 Proceedings of the 12th International Conference on Very Large Data Bases
Theory of Relational Databases
Theory of Relational Databases
Unique complements and decompositions of database schemata
Journal of Computer and System Sciences
Component-driven engineering of database applications
APCCM '06 Proceedings of the 3rd Asia-Pacific conference on Conceptual modelling - Volume 53
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A generalized approach to the decomposition of relational schemata is developed in which the component views may be defined using both restriction and projection operators, thus admitting both horizontal and vertical decompositions. The realization of restrictions is enabled through the use of a Boolean algebra of types, while true independence of projections is modelled by permitting null values in the base schema. The flavor of the approach is algebraic, with the collection of all candidate views of a decomposition modelled within a lattice-like framework, and the actual decompositions arising as Boolean subalgebrac. Central to the framework is the notion of sidimensional join dependency, which generalizes the classical notion of join dependency by allowing the components of the join to be selected horizontally as well as vertically. Several properties of such dependencies are presented, including a generalization of many of the classical results known to be equivalent to schema acyclicity. Finally, a characterization of the nature of dependencies which participate in decompositions is presented. It is shown that there are two major types, the bidimensional join dependencies, which are tuple generating and allow tuple removal by implicit encoding of knowledge, and splitting dependencies, which simply partition the database into two components.