Chapter 8, Problem 12E

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 names of all people who are not secretaries

Query

select name from person where not exists

(select value(e) from employee e where value(e) is of (Secretary))

Explanation

• The “is of” type predicate is used to test object instance of a particular subtype or not...

c.

Explanation of Solution

SQL query to print the names of people who are neither employees nor students

Query

select name from person where not exists

((select value(p) from person p where value(p) is of (employee)) and (select value(p) from person p where value(p) is of (student))...

d.

Explanation of Solution

Reason for not creating a person who is an employee and a student

“No”, a person who is both an employee and a student cannot be created.

Reason

• Structured Query Language (SQL) does not support multiple inheritance.
• Different tables are used to store an employee or a student...