Extending the database relational model to capture more meaning
ACM Transactions on Database Systems (TODS)
Relational database: a practical foundation for productivity
Communications of the ACM
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
Null values in data base management a denotational semantics approach
SIGMOD '79 Proceedings of the 1979 ACM SIGMOD international conference on Management of data
Incomplete information and the join operation in database machines
ACM '87 Proceedings of the 1987 Fall Joint Computer Conference on Exploring technology: today and tomorrow
Imprecise information and uncertainty in information systems
ACM Transactions on Information Systems (TOIS)
Incomplete information in object-oriented databases
ACM SIGMOD Record
ANNA '91 Proceedings of the conference on Analysis of neural network applications
Semantics for null extended nested relations
ACM Transactions on Database Systems (TODS)
A probabilistic relational algebra for the integration of information retrieval and database systems
ACM Transactions on Information Systems (TOIS)
Four valued logic for relational database systems
ACM SIGMOD Record
Nulls in relational databases: revised
ACM SIGMOD Record
An extension of the relational data model to incorporate ordered domains
ACM Transactions on Database Systems (TODS)
Data mining for design and manufacturing
Searching a minimal semantically-equivalent subset of a set of partial values
The VLDB Journal — The International Journal on Very Large Data Bases
An Exploration of Relationships Among Exclusive Disjunctive Data
IEEE Transactions on Knowledge and Data Engineering
Evaluating Aggregate Operations Over Imprecise Data
IEEE Transactions on Knowledge and Data Engineering
Efficient Query Processing in Integrated Multiple Object Databases with Maybe Result Certification
IEEE Transactions on Knowledge and Data Engineering
Semantic Conflicts and Solutions in Fuzzy Multidatabase Systems
DNIS '00 Proceedings of the International Workshop on Databases in Networked Information Systems
Closed World Databases Opened Through Null Values
VLDB '88 Proceedings of the 14th International Conference on Very Large Data Bases
A Probabilistic Framework for Vague Queries and Imprecise Information in Databases
VLDB '90 Proceedings of the 16th International Conference on Very Large Data Bases
Referential Integrity Revisited: An Object-Oriented Perspective
VLDB '90 Proceedings of the 16th International Conference on Very Large Data Bases
Infinite Relations in Paraconsistent Databases
ADBIS '99 Proceedings of the Third East European Conference on Advances in Databases and Information Systems
Temporal Databases with Null Values
DEXA '00 Proceedings of the 11th International Conference on Database and Expert Systems Applications
Entity identification of fuzzy multidatabase systems with incompatible keys
Web-enabled systems integration
The development of ordered SQL packages to support data warehousing
Data warehousing and web engineering
A tuple-oriented algorithm for deduction in a fuzzy relational database
International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems - Intelligent information systems
Missing and inapplicable values
ACM SIGMOD Record
Integrating XML and Relational Database Systems
World Wide Web
Null values in fuzzy databases
Journal of Intelligent Information Systems
Flexible querying in a relational framework supported by possibilistic logic
Fuzzy Sets and Systems
Aliança: A proposal for a fuzzy database architecture incorporating XML
Fuzzy Sets and Systems
IJCAI'91 Proceedings of the 12th international joint conference on Artificial intelligence - Volume 2
A new extension of fuzzy sets using rough sets: R-fuzzy sets
Information Sciences: an International Journal
Consistency enforcement in databases
Proceedings of the 2nd international conference on Semantics in databases
An extension of SQL to support ordered domains in relational databases
IDEAS'97 Proceedings of the 1997 international conference on International database engineering and applications symposium
Treating incomplete knowledge in formal concept analysis
Formal Concept Analysis
Completeness of queries over SQL databases
Proceedings of the 21st ACM international conference on Information and knowledge management
Finite type extensions in constraint programming
Proceedings of the 15th Symposium on Principles and Practice of Declarative Programming
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There has been some technical and justified criticism of the treatment of missing information in the data sublanguage SQL and in IBM's Database 2 system (a relational database management system). Some of this criticism has been directed (by mistake) at the relational model. The purpose of this paper is to clarify and extend the treatment of missing information by the relational model.The clarification places heavy emphasis on the semantic aspects of missing information. The extension, which is relatively minor, provides a systematic approach (independent of data type) to dealing with the inapplicability of certain properties to some objects. This extension does not invalidate any part of the present version of the relational model.