Exercise 6.6.1:

This and the next exercises involve certain programs that operate on the two relations

Product(maker, model, type)

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

from our running PC exercise.

. a) Given a speed and amount of RAM (as arguments of the function), look up the PCs with that speed and RAM, printing the model number and price of each.

b) Given a model number, delete the tuple for that model from both PC and Product.

c) Given a model number, decrease the price of that model PC by $100.

d) Given a maker, model number, processor speed, RAM size, hard-disk size, and price, check that there is no product with that model. If there is such a model, print an error message for the user. If no such model existed in the database, enter the information about that model into the PC and Product tables

Question. 3. Exe. 6.6.3 (30 pts). Base your answers on the SQL standard definitions of isolation levels.

Use the following format for your answers:

(a) when T is the READ ONLY transaction from 6.6.1(a)

If another READ ONLY transaction runs concurrently 1) Under read uncommitted, . 2) Under serializable, .

If the other concurrent transaction is deleteModel from 6.6.1 (b), 1) Under read uncommitted, . 2) Under serializable, .

If the other concurrent transaction is updatePCPrice from 6.6.1(c), 1) Under read uncommitted, . 2) Under serializable, .

If the other concurrent transaction is insertPC from 6.6.1 (d), 1) Under read uncommitted, . 2) Under serializable, .

(b) when T is the deleteModel transaction from 6.6.1(b)

If the other concurrent transaction is deleteModel from 6.6.1 (b), 1) Under read uncommitted, . 2) Under serializable, .

If the other concurrent transaction is updatePCPrice from 6.6.1(c), 1) Under read uncommitted, . 2) Under serializable, .

If the other concurrent transaction is insertPC from 6.6.1 (d), 1) Under read uncommitted, . 2) Under serializable, .

(c) when T is the updatePCPrice transaction from 6.6.1(c)

If the other concurrent transaction is updatePCPrice from 6.6.1(c), 1) Under read uncommitted, . 2) Under serializable, .

If the other concurrent transaction is insertPC from 6.6.1 (d), 1) Under read uncommitted, . 2) Under serializable, .

(d) when T is the insertPC transaction from 6.6.1(d)

If the other concurrent transaction is insertPC from 6.6.1 (d), 1) Under read uncommitted, . 2) Under serializable, .