Let R = (A, B) and S = (A, C), and let r(R) and s(S) be relations.

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Let R = (A, B) and S = (A, C), and let r(R) and s(S) be relations. Using the special constant null, write tuple-relational-calculus expressions equivalent to each of the following:

a. r 1 s

b. r 1 s

c. r 1 s

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Database System Concepts

ISBN: 978-0072554816

4th Edition

Authors: Henry F. Korth, S. Sudarshan

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Question Posted: Jan 28, 2011 05:54 AM

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Let R = (A, B) and S = (A, C), and let r(R) and s(S) be relations.

Question:

Step by Step Answer:

a t r R s S rA sA tA rA tB rB tC sC s S r RrA sA tA sA tC sC tB n...View the full answer

Database System Concepts

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