Exercise 6.5.1: Write the following database modifications, based on the databas

Question

Exercise 6.5.1: Write the following database modifications, based on the

database schema

Product(maker, model, type)

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

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

Printer(model, color, type, price)

a) Using two INSERT statements, store in the database the fact that PC

model 1100 is made by manufacturer C, has speed 3.2, RAM 1024, hard

disk 180, and sells for $2499.

! b) Insert the facts that for every PC there is a laptop with the same manufacturer,

speed, RAM, and hard disk, a 17-inch screen, a model number

1100 greater, and a price $500 more.

c) Delete all PC's with less than 100 gigabytes of hard disk.

d) Delete all laptops made by a manufacturer that doesn't make printers.

e) Manufacturer A buys manufacturer B. Change all products made by B so

they are now made by A.

f) For each PC, double the amount of RAM and add 60 gigabytes to the

amount of hard disk. (Remember that several attributes can be changed

by one UPDATE statement.)

! g) For each laptop made by manufacturer B, add one inch to the screen size

and subtract $100 from the price.

Explanation / Answer

a)

insert into Product('C',1100,'PC');

insert into PC(1100,3.2,1024,180,2499);

! b)

insert into Product('C',1100,'Laptop');

insert into Laptop(2200, 3.2,1024,180, 17, 2999);

c)

Delete from PC where hd <100;

d)

Delete from Laptop where Maker = (Select maker from Product where type != 'Printer');

e)

Update product set maker = 'A' where maker = 'B';

f)

Update PC set ram = 2*ram and hd = hd +60;

! g)

Update laptop set screen = screen +1 and price = price - 100 where maker = 'B';

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