Consider the following SQL query for our bank database select T.branch-name from branch T, branch S where T.assets > S.assets and S.branch-city = “Brooklyn” Write an efficient relational-algebra expression that is equivalent to this query. Justify your choice.
Answer to relevant QuestionsWhat are the advantages and disadvantages of hash indices relative to B+-tree indices? How might the type of index available influence the choice of a query processing strategy?Estimate the number of block accesses required by your solution to Exercise for r1 Θ r2, where r1 and r2 are as defined in Exercise.Consider the relations r1 (A, B, C), r2 (C, D, E), and r3 (E, F), with primary keys A, C, and E, respectively. Assume that r1 has 1000 tuples, r2 has 1500 tuples, and r3 has 750 tuples. Estimate the size of r1 Θ r2 ...Show that, with n relations, there are (2(n − 1))! / (n−1)! Different join orders. If you wish, you can derive the formula for the number of complete binary trees with n nodes from the formula for the number of ...Consider a file system such as the one on your favorite operating system.a. What are the steps involved in creation and deletion of files, and in writing data to a file?b. Explain how the issues of atomicity and durability ...
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