Consider the following relational database that stores information about computer hardware products (keys are underlined, field types are omitted): Product (maker, model, type) PC (model, speed, ram, hd, price) Laptop (model, speed, ram, hd, screen, price) Printer (model, color, type, price) The Product relation gives the manufacturer, model number and type (PC/laptop/printer) of various products. The PC relation gives for each model number that is a PC the speed (of the processor, in gigahertz), the amount of RAM (in GB), the size of hard disk (in GB), and the price. The Laptop relation is similar, with screen size included. The Printer relation records whether it is a color printer or not (Yes/No), and the type (laser/ink-jet) and the price. Write the following queries in relational algebra: Q3.1. (2 points) Find the model numbers of all color laser printers. Q3.2. (3 points) Find the model number and price of all products (of any type) made by manufacturer HP. Q3.3. (5 points) Find those manufacturers of at least two different computers (PCs or laptops) with speeds of at least 2.80. Hint: You may need a self Cartesian product and a join. Q3.4. (6 points) Find the manufacturers who sell exactly three different models of PC. Hint: Similar in spirit to Q3.3, but you may have to use the set difference as well. Q3.5. (6 points) Find the manufacturers who sell PCs with at least the set of all the RAM sizes seen in laptops.

Q3. RA: Products and Manufacturers [22 points] Consider the following relational database that stores information about computer hardware products (keys are underlined, field types are omitted) Product (maker, model, type) PC (model, speed, ram, hd, price) Laptop (model, speed, ram, hd, screen, price) Printer (model, color, type, price) The Product relation gives the manufacturer, model number and type (PC/laptop/printer) of various products. The PC relation gives for each model number that is a PC the speed (of the processor, in gigahertz), the amount of RAM (in GB), the size of hard disk (in GB), and the price. The Laptop relation is similar, with screen size included. The Printer relation records whether it is a color printer or not (Yes/No), and the type (laser/ink-jet) and the price Write the following queries in relational algebra Q3.1. (2 points) Find the model numbers of all color laser printers. Q3.2. (3 points) Find the model number and price of all products (of any type) made bv manufacturer 'HP Q3.3. (5 points) Find those manufacturers of at least two different computers (PCs or laptops) with speeds of at least 2.80 Hint: You may need a 'self Cartesian product and a join. Q3.4. (6 points) Find the manufacturers who sell exactly three different models of Hint: Similar in spirit to Q3.3, but you may have to use the set difference as Q3.5. (6 points) Find the manufacturers who sell PCs with at least the set of all the PC. well. RAM sizes seen in laptops