Consider the following BCNF relations, which describe departments in a company and employees:
Dept(did, dname, location, managerid) Emp(eid, sal)
You are told that the following queries are extremely important:
List the names and ids of managers for each department in a user-speci?ed loca-tion, in alphabetical order by department name.
Find the average salary of employees who manage departments in a user-speci?ed location. You can assume that no one manages more than one department.
1. Describe the ?le structures and indexes that you would choose.
2. You subsequently realize that updates to these relations are frequent. Because indexes incur a high overhead, can you think of a way to improve performance on these queries without using indexes?