2005 Spring

Database Homework 3

Deadline 2005-04-21

Please refer to the following relation schemas to answer questions using relational algebra.

SALESPERSON	Name	Salary
	Baker	42,000
	Jones	36,000
	…	…

ORDER	Number	CustName	SalespersonName	Amount
	100	Abernathy Construction	Zenith	560
	300	Manchester Lumber	Abel	480
	…	…	…	…

CUSTOMER	Name	City	IndustryType
	Abernathy Construction	Willow	B
	Manchester Lumber	Manchester	F
	…	…	…

1. Retrieve the names of all salespersons.

2. Retrieve the names of all salespersons having an “order”.

3. Retrieve the names of salespersons not having an “order”.

4. Retrieve the names of salespersons having an order with Abernathy Construction.

5. Retrieve the salaries of salespersons having an order with Abernathy Construction.

6. Retrieve the city of all customers having an order with salesperson Jones

7. Retrieve the names of all salespersons with the names of customers who have ordered from them. Include salespersons who have no orders.