Q1: The select (o) operation and (∞) join operations are commutative. Give one scenario or case under which the right hand side of the following equivalence rule is more efficient that its left hand side, explain your answer: (1) Oc1(0c2(R)) = 0c2(0c1(R)) (2) Rab S = S 00a-b R (when nested block join algorithm is used) Where ∞ is an equi-join operation R and S are tables a is an attribute in R b is an attribute in S c1, and c2 are conditions

Q1: The select (o) operation and (∞) join operations are commutative. Give one scenario or case under which the right hand side of the following equivalence rule is more efficient that its left hand side, explain your answer: (1) Oc1(0c2(R)) = 0c2(0c1(R)) (2) Rab S = S 00a-b R (when nested block join algorithm is used) Where ∞ is an equi-join operation R and S are tables a is an attribute in R b is an attribute in S c1, and c2 are conditions

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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How to code in Python or Java below Algorithm # 10 General Algorithm for Testing Loosless Join DecompositionInput: A universal relation R, a decomposition D={R1,R2,...Rm}of R , and a set F of functional dependencies.1. Create an initial matrix S with one row for each relation Riin D, and one column for each attribute Aj in R.2. Set S(i,j)= bij for all matrix entries.( Note that each bij isa distinct symbol associated with indices (i,j) ).3. For each row i representing relation schema RiFor each column j representing attribute AjIF the relation Ri includes attribute Aj then set S(i,j)= aj.( Note that aj is a distinct symbol associated with index j)4. Repeat the following loop until a complete loop execution results in no changes to SFor each functional dependency X→Y in FFor all rows in S that have the same symbols in the columns corresponding toattributes in X.Make the symbols in each column that correspond to anattribute in Y be the same in all these rows as follows:▪ If any of the…
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