Nest and Unnest Operators in Nested Relations

Data Science Journal

Georgia Garani¹ 

[1] Dept of Computer Science and Telecommunications, Technological Educational Institute, Larissa 41110, Greece;

关键词: Non-First Normal Form database;    Nested relation;    Decomposable nested attribute;   

DOI  :  10.2481/dsj.7.57

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown