Chapter 8, Problem 6PE

a.

Explanation of Solution

SQL schema definition

• Person relation type is considered.

  create type Person (ID integer, name varchar (30), address varchar (50))

  create table person of Person

• Employee relation type is considered.

  create type Employee under Person (salary integer)

  create table employee of Employee under person

• Student relation type is considered...

b.

Explanation of Solution

SQL query to find the company with the most employees

Query

select comp -> name from works group by comp having count(person)>= all (select count(person)from works group by comp)

Explanation

• The “group by” clause is used to group rows that have same values.
• This query is used to get the company that has most employees.

SQL query to find the company with the smallest payroll

Query

select comp -> name from works group by comp having sum(salary)<= all (select sum(salary)from works group by comp)

Explanation

• The “group by” clause is used to group rows that have same values...