The first step in optimizing a query is

Selection condition: (age = 40 v  GPA >3.5) ∧  years > 2 (assuming age, GPA, and years are in the same relation) Which index(es) below that is/are most effective in executing this query with the above-mentioned selection condition?

Consider a relation R with five attributes X, Y, Z, W, V. You are given the following dependencies: {X -> Y, YZ-> W, X->Z} List all candidate keys for R. Please justify your answer.   Is R in 3NF? Please justify.   Is R in BCNF? Please justify.

What is wrong with the following query?                       SELECT sname, count(snum)                 FROM Enroll;

What is the information stored in a catalog of database (in which metadata is stored) ?

Given a relation Criminal(id, name, crime) containing 1,000,000 records, where each data page of the relation holds 100 records. Assume that Criminal.id is a candidate key for this relation, with values lying in the range 0 to 999,999, and that Criminal is stored and sorted in Criminal.id order. a. For each of the following relational algebra queries: (i)

Which one of the following statements about normal forms is FALSE?

Several animals in a group are consuming less feed than expected, while others maintain normal intake on the same ration. What is the most likely explanation?

What is the primary difference between an as-fed and dry matter analysis of a feed?

Why can ruminants utilize microbial protein more effectively than hindgut fermenters?