Interactions between dependencies and nested relational structures
Journal of Computer and System Sciences
Functional dependencies and constraints on Null values in database relations
Information and Control
Reasoning about functional dependencies generalized for semantic data models
ACM Transactions on Database Systems (TODS)
Semantics for null extended nested relations
ACM Transactions on Database Systems (TODS)
Object normal forms and dependency constraints for object-oriented schemata
ACM Transactions on Database Systems (TODS)
Axiomatisation of functional dependencies in incomplete relations
Theoretical Computer Science
Reasoning about nested functional dependencies
PODS '99 Proceedings of the eighteenth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Temporal FDs on complex objects
ACM Transactions on Database Systems (TODS)
Computational problems related to the design of normal form relational schemas
ACM Transactions on Database Systems (TODS)
Extending the database relational model to capture more meaning
ACM Transactions on Database Systems (TODS)
Normalization and hierarchical dependencies in the relational data model
ACM Transactions on Database Systems (TODS)
Synthesizing third normal form relations from functional dependencies
ACM Transactions on Database Systems (TODS)
Multivalued dependencies and a new normal form for relational databases
ACM Transactions on Database Systems (TODS)
On Axiomatizing Multivalued Dependencies in Relational Databases
Journal of the ACM (JACM)
An Almost Linear-Time Algorithm for Computing a Dependency Basis in a Relational Database
Journal of the ACM (JACM)
On the Equivalence of Database Models
Journal of the ACM (JACM)
A relational model of data for large shared data banks
Communications of the ACM
A complete axiomatization for functional and multivalued dependencies in database relations
SIGMOD '77 Proceedings of the 1977 ACM SIGMOD international conference on Management of data
Dependency Satisfaction in Databases with Incomplete Information
VLDB '84 Proceedings of the 10th International Conference on Very Large Data Bases
Closed World Databases Opened Through Null Values
VLDB '88 Proceedings of the 14th International Conference on Very Large Data Bases
Analysis and design of relational schemata for database systems.
Analysis and design of relational schemata for database systems.
A normal form for XML documents
ACM Transactions on Database Systems (TODS)
Multi-valued dependencies in the presence of lists
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
On a problem of Fagin concerning multivalued dependencies in relational databases
Theoretical Computer Science
A consideration on normal form of not-necessarily-normalized relation in the relational data model
VLDB '77 Proceedings of the third international conference on Very large data bases - Volume 3
What does Boyce-Codd normal form do?
VLDB '80 Proceedings of the sixth international conference on Very Large Data Bases - Volume 6
Multivalued dependencies in XML
BNCOD'03 Proceedings of the 20th British national conference on Databases
On multivalued dependencies in fixed and undetermined universes
FoIKS'06 Proceedings of the 4th international conference on Foundations of Information and Knowledge Systems
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The implication of multivalued dependencies (MVDs) in relational databases has originally been defined in the context of some fixed finite universe (Fagin 1977, Zaniolo 1976). While axiomatisability, implication problem and many design problems have been intensely studied with respect to this notion, almost no research has been devoted towards the alternative notion of implication in which the underlying universe of attributes is left undetermined (Biskup 1980). A milestone in the advancement of database systems was the permission of null values in databases. In particular, many achievements on MVDs have been extended to encompass incomplete information. Multivalued dependencies with null values (NMVDs) were defined and axiomatised in (Lien 1982). The definition of NMVDs is again based on a fixed underlying universe of attributes, and any complete set of inference rules requires therefore some version of the complementation rule. In this paper we show that the axiomatisation in (Lien 1982) does not reflect the fact that the complementation rule is merely a means to achieve database normalisation. Moreover, we provide an alternative axiomatisation for NMVDs that does reflect this property. We also suggest an alternative notion for the implication of NMVDs in which the underlying universe is left undetermined, and propose several sound and complete sets of inference rules for this notion. Moreover, a correspondence between (minimal) axiomatisations in fixed universes that do reflect the property of complementation and (minimal) axiomatisations in undetermined universes is shown.