Question: In Chapter 3 we described the use of views to
In Chapter 3, we described the use of views to simplify access to the database by users who need to see only part of the database. In this chapter, we described the use of views as a securitymechanism. Do these two purposes for views ever conflict? Explain your answer.
Answer to relevant QuestionsWhat is the purpose of having separate categories for index authorization and resource authorization?Suppose that we decompose the schema R = (A, B, C, D, E) into (A, B, C) (A, D, E). Show that this decomposition is a loss less-join decomposition if the following set F of functional dependencies holds: A → BC CD ...Use Armstrong’s axioms to prove the soundness of the decomposition rule.Let R1, R2, Rn be a decomposition of schema U. Let u (U) be a relation, and let r i = IIRI (a). Show that u ⊆ r1 1 r2 1 • • • 1 rnA functional dependency α → β is called a partial dependency if there is a proper subset γ of α such that γ → β.We says that β is partially dependent on α. A relation ...
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