# Question

Suppose that a B + - tree index on branch-city is available on relation branch, and that no other index is available. List different ways to handle the following selections that involve negation?

a. σ ¬ ((branch-city <“Brooklyn”)(branch)

b. σ ¬ (branch-city=“Brooklyn”)(branch)

c. σ ¬ ((branch-city <“Brooklyn” ∨ assets<5000)(branch)

a. σ ¬ ((branch-city <“Brooklyn”)(branch)

b. σ ¬ (branch-city=“Brooklyn”)(branch)

c. σ ¬ ((branch-city <“Brooklyn” ∨ assets<5000)(branch)

## Answer to relevant Questions

The hash join algorithm as described in Section computes the natural join of two relations. Describe how to extend the hash join algorithm to compute the natural left outer join, the natural right outer join and the natural ...Consider the relations r1 (A, B, C), r2 (C, D, E), and r3 (E, F) of Exercise. Assume that there are no primary keys, except the entire schema. Let V (C, r1) be 900, V (C, r2) be 1100, V (E, r2) be 50, and V (E, r3) be 100. ...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 ...Suppose that there is a database system that never fails. Is a recovery manager required for this system?What is a recoverable schedule? Why is recoverability of schedules desirable? Are there any circumstances under which it would be desirable to allow nonrecoverable schedules? Explain your answer.Post your question

0