DATABASE APPLICATIONS

Given the following tables

Product(maker, model, type)

PC(model, speed, ram, hd, price)

Laptop(model, speed, ram, hd, screen, price)

Printer(model, color, type, price)

Retrieve the following information by using a series of relational algebraic operations.

1- What PC models (model number) have a speed of at least 3.00?

2- Find the model numbers of all color laser printers.

* The color attribute tells if the printer is color or not.

* The type attribute tells if the printer is laser or inkjet.

3- Find those manufacturers (maker) that sell Laptops, but not PCs.

4- Find the model number and price of all products (of any type) made by manufacturer B.

5- Which manufacturers (maker) make laptops with a hard disk of at least 100GB?

6-Find those hard-disk sizes that occur in two or more PCs.