For the purpose of tuning your database that has begun to slow down for some queries, you are looking for the best plan to execute the following queries on the relation described below: The relation you are dealing with is Employee with attributes ename, title, dname, and address; all are string fields of the same length. The ename attribute is a candidate key. The relation contains 10,000 pages. There are 10 buffer pages. (When answering the questions, make sure to describe the plan you have in mind.)
The first query is: SELECT E. title, E. ename FROM Employee E WHERE E. title=‘Administrator’ Assume that only 10% of Employee tuples meet the selection condition.
a. Suppose that a clustered B+ tree index on ename is (the only index) available. What is the cost of the best plan? (5 marks)
Candidate key is ename Relation contains 10,000 pages, 10 buffer pages Therefore, the cost G is the best plan = 10,000
b. Suppose that a clustered B+ tree index on title is (the only index) available. What is the cost of the best plan? (5 marks)
c. Suppose that a clustered B+ tree index on dname is (the only index) available. What is the cost of the best plan? (5 marks)
d. Suppose that a clustered B+ tree index on is (the only index) available. What is the cost of the best plan? (5 marks)