Show how to derive the following equivalences by a sequence of transformations using the equivalence rules in

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Show how to derive the following equivalences by a sequence of transformations using the equivalence rules in Section 14.3.1.

a. σ_θ1 ∧ _θ2 ∧ _θ3 (E) = σ_θ1 (σ_θ2 (σ_θ3 (E)))

b. σ_θ1 ∧ _θ2(E₁ 1_θ3 E₂) = σ_θ1 (E₁ 1_θ3 (σ_θ2 (E₂))), where θ₂ involves only attributes from E₂

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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 29, 2011 01:42 AM

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Show how to derive the following equivalences by a sequence of transformations using the equivalence rules in

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a Using rule 1 00003 E becomes E ...View the full answer

Database System Concepts

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