Using semi-joins to solve relational queries
Author(s)
Author(s)
Bernstein, P. A.
Date Issued
1981
Publisher
Association for Computing Machinery
Journal
Journal of the ACM
Volume
28
Issue
1
Start page
25
End page
40
Abstract
The semi-join is a relational algebraic operation that selects a set of tuples in one relation that match one or more tuples of another relation on the joining domains. Semi-joins have been used as a basic ingredient in query processing strategies for a number of hardware and software database systems. However, not all queries can be solved entirely using semi-joins. In this paper the exact class of relational queries that can be solved using semi-joins is shown. It is also shown that queries outside of this class may not even be partially solvable using "short" semi-join programs. In addition, a linear-time membership test for this class is presented.
SFU Affiliated Publication
No
Availability at SFU Library
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