Incomplete information in a relational database

1980 ◽  
Vol 3 (3) ◽  
pp. 363-377
Author(s):  
John Grant
Keyword(s):  
Incomplete Information ◽  
Relational Database ◽  
Functional Dependency ◽  
Relational Algebra ◽  
Database Model ◽  
Character String

In this paper we investigate the inclusion of incomplete information in the relational database model. This is done by allowing nonatomic entries, i.e. sets, as elements in the database. A nonatomic entry is interpreted as a set of possible elements, one of which is the correct one. We deal primarily with numerical entries where an allowed set is an interval, and character string entries. We discuss the various operations of the relational algebra as well as the notion of functional dependency for the database model.

scholarly journals A New Approach of Functional Dependency in a Neutrosophic Relational Database Model

2019 ◽  
Vol 8 (2) ◽  
pp. 44-48
Author(s):  
Soumitra De ◽  
Jaydev Mishra
Keyword(s):  
Relational Database ◽  
Classical Case ◽  
Functional Dependency ◽  
Neutrosophic Set ◽  
Uncertain Information ◽  
Neutrosophic Sets ◽  
New Approach ◽  
Vague Set ◽  
Database Model ◽  
Relational Data Model

In order to model the imprecise and uncertain information, different classical relational data model have been studied in literature using vague set theory. However, neutrosophic set, as a generalized vague set, has more powerful ability to process fuzzy information than vague set. In this paper, we have proposed a neutrosophic relational database model and have defined a new kind of neutrosophic functional dependency (called  -nfd) based on the -equality of tuples and the similarity measure of neutrosophic sets. Next, we present a set of sound neutrosophic inference rules which are similar to Armstrong’s axioms for the classical case. Finally, partial  -nfdand neutrosophic key have been studied with the new notion of  -nfdand also tested.

scholarly journals A probabilistic relational database model and algebra

2015 ◽  
Vol 31 (4) ◽  
pp. 305
Author(s):  
Hoa Nguyen
Keyword(s):  
Relational Database ◽  
Functional Dependency ◽  
Uncertain Information ◽  
Database Model ◽  
Algebraic Operations ◽  
And Algebra ◽  
Attribute Value

This paper introduces a probabilistic relational database model, called PRDB, for representing and querying uncertain information of objects in practice. To develop the PRDB model, first, we represent the relational attribute value as a pair of probabilistic distributions on a set for modeling the possibility that the attribute can take one of the values of the set with a probability belonging to the interval which is inferred from the pair of probabilistic distributions. Next, on the basis representing such attribute values, we formally define the notions as the schema, relation, probabilistic functional dependency and probabilistic relational algebraic operations for PRDB. In addition, a set of the properties of the probabilistic relational algebraic operations in PRDB also are formulated and proven.

Research Background

2013 ◽  
pp. 187-200
Author(s):  
Ibrahim Dweib ◽  
Joan Lu
Keyword(s):  
Data Storage ◽  
Relational Database ◽  
Query Languages ◽  
Xml Schema ◽  
Application Program Interface ◽  
Database Model ◽  
Xml Documents ◽  
Similarities And Differences ◽  
Schema Languages ◽  
Program Interface

In this chapter, the research background is discussed. This includes XML model, XML query languages, XML schema languages, XML Application Program Interface, XML documents types, XML data storage approaches, relational database model, and the similarities and differences between XML model and relational database model. Finally the chapter summary is given.

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