Multivalued dependencies and a new normal form for relational databases
ACM Transactions on Database Systems (TODS)
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
IJCAI'91 Proceedings of the 12th international joint conference on Artificial intelligence - Volume 2
NULL 'Value' Algebras and Logics
Proceedings of the 2011 conference on Information Modelling and Knowledge Bases XXII
Exploiting data dependencies with null values for ontology extraction
ER'12 Proceedings of the 31st international conference on Conceptual Modeling
| Hi-index | 0.01 |
The role of null values in a relational data base is considered within the framework of multivalued dependencies. When a relation contains null values, a different treatment of data dependencies and different relational operations such as projection and join, are necessary. This paper develops a complete axiomatization for the revised multivalued dependencies. In particular, complementation, reflexivity, augmentation, and union are shown to be a complete set of inference rules. In contrast with the conventional multivalued dependencies, the transitivity rule cannot be used. These results provide a framework for the use of the revised multivalued dependencies in choosing relations and their attributes for a feasible data-base design.