1. The following database Supply (Company, part, Qty) Storage (Department, part,

ID: 3891644 • Letter: 1

Question

1. The following database

Supply (Company, part, Qty)

Storage (Department, part, Qty)

find all parts and their quantity used by “ computer science” department.

find all companies which supply at least one part used by” computer science” department

find all companies supply all the parts be “ computer science” department.

2. The following database

deposit (bank_account, account_number, costumer_name, balance)

barrow (bank_name, last_ name, costumer_name, account)

Find all customers who have only a deposit account whose balance is greater than $ 1000.

Find all customers who have only a deposit account at (Chester) branch and whose balance greater than $ 2500.

Find all customers who have both a deposit account and a loan at (Chester) branch.

3. One of the set operators (-x) can be expressed in terms of the other set operators .

which one is it? give the algebraic expression in terms of the other set operators.

hint: R S = (RS) x (R-S)

4. give an algebraic expression for the join operation in terms of other relation algebra operations.

6. Under what condition is the following equation true ?

A1(R)= R

1. SELECT part, Qty FROM Storage WHERE Department = 'computer science';

SELECT Company FROM Supply WHERE count(*) >= 1 GROUP BY Company;

SELECT Company, part FROM Supply WHERE part in (SELECT part FROM Storage WHERE Department = 'computer science');

2. SELECT * FROM depost WHERE balance > 1000;

SELECT * FROM depost WHERE balance > 2500 AND account_number IN (SELECT account FROM barrow WHERE bank_name = 'Chester');

3. The division operator can be expressed as

R÷S=?A(R)??A(?A(R)×S?R)

4. ? (STUDENT.ROLL_NO>EMPLOYEE.EMP_NO)(STUDENT×EMPLOYEE)

NOTE: As per Chegg policy, I could answer only 4 questions at a time. Please post the remaining questions separately and I will try to answer it.

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