Functional dependencies and constraints on Null values in database relations
Information and Control
The relational model for database management: version 2
The relational model for database management: version 2
A fact-oriented approach to schema transformation
MFDBS 91 Proceedings of the 3rd symposium on Mathematical fundamentals of database and knowledge base systems
Converting OO Models Into RDBMS Schema
IEEE Software
Conceptual design of object-oriented database schemas using the binary-relationship model
Data & Knowledge Engineering
Supporting schema integration by linguistic instruments
Data & Knowledge Engineering - Special issue natural language for data bases
Formal Ontology in Information Systems: Proceedings of the 1st International Conference June 6-8, 1998, Trento, Italy
Understanding semantic relationships
The VLDB Journal — The International Journal on Very Large Data Bases
Deriving Normalized Is_a Hierarchies by Using Applicability Constraints
CAiSE ;96 Proceedings of the 8th International Conference on Advances Information System Engineering
Functional Dependencies and Disjunctive Existence Constraints in Database Relations with Null Values
Proceedings of the 11th Colloquium on Automata, Languages and Programming
An Algorithm to Extract IS-A Inheritance Hierarchies from a Relational Database
ER '99 Proceedings of the 18th International Conference on Conceptual Modeling
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"Is_A" links are the core component of all ontologies and are organized into "hierarchies of concepts". In this paper we will first address the problem of an automatic help to build sound hierarchies. Dependencies called "existence constraints" are the foundation for the definition of a "normalized " hierarchy of concepts. In the first part of the paper algorithms are provided to obtain a normalized hierarchy starting either from concepts or from instances using Boolean functions. The second part of the paper is devoted to the hierarchy maintenance: automatically inserting, merging or removing pieces of knowledge. We also provide a way to give synthetic views of the hierarchy.