Nest and Unnest Operators in Nested Relations

By distinguishing nested attributes as Decomposable and Non-Decomposable, it is proved that for all nested relations, unnesting and then renesting on the same attribute yields the original relation subject only to the elimination of duplicate data. Therefore, the statement that was popular in nested...

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Bibliographic Details
Main Author: Georgia Garani
Format: Article
Language:English
Published: Ubiquity Press 2008-05-01
Series:Data Science Journal
Subjects:
Online Access:http://datascience.codata.org/articles/319
Description
Summary:By distinguishing nested attributes as Decomposable and Non-Decomposable, it is proved that for all nested relations, unnesting and then renesting on the same attribute yields the original relation subject only to the elimination of duplicate data. Therefore, the statement that was popular in nested relations research: "Unnesting and then nesting on the same attribute of a nested relation does not always yield the original relation" is reconsidered.
ISSN:1683-1470