Incremental Evaluation of Nest and Unnest Operators in Nested Relations
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چکیده
Incremental expressions are important in materialized view maintenance, query optimization, and constraint checking. In this paper, we derive incremental expressions for the nest and unnest operators in nested relations. The expressions are derived for both general nested relations using set operators for updating relations and for partition-normal form (PNF) relations using extended set operators for updating relations After deriving the incremental expressions, two algorithms are presented for maintaining views deened by nest and unnest operators in PNF.
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تاریخ انتشار 1999