The Nested Universal Relation Database Model

Equivalence of the Relational Algebra a N D Calculus for Nested Relations

Abstrac t -The relational model is extended to include nested structures. This extension is formalised using the distinction between a tuple scheme and a relation scheme. The algebra and calculus languages are defined for this model. It is shown that the restricted powerset is a derived operation in the algebra and the full powerset is expressible by a safe forraula in the calculus. Since the f...

Maintaining Semi-structured Spatio-Temporal Data Based on Nesting-Relation-Oriented Model

semi-structured spatio-Temporal data has become prevalent with growth of GIS. In this paper, we propose to use “Nested” natural of spatio-Temporal data to storing & maintaining it efficiently in an Object-Relational Database based on Nesting-Relation-Oriented data Model– one of N1NF database. This model not only reflects the nested structure of semi-structured spatio-Temporal data, but also dis...

NF-NR: A practical normal form for nested relations

We propose a normal form for nested relations, called NF-NR, which removes undesirable anomalies from a nested relational database schema. Both functional dependencies and multivalued dependencies are considered. NF-NR reduces to 3NF/4NF if the nested relation considered is actually a flat relation. Especially, NF-NR removes global redundancies among a set of nested relations. Two approaches to...

Detection of the phytoplasmal agent of pear decline in Iran, Isfahan province, using nested-PCR

Pear decline is a very important phytoplasma disease that causes considerable quantitative and qualitative losses to this fruit crop. Due to economical importance of pear in Isfahan province, Iran, and the difficulty to determine the occurrence of the disease simply based on symptoms in orchards, a detection method for the phytoplasma causing disease in pears in the region was developed. Since ...

The Nested Universal Relation Data Model