Relation Algebra|computer science
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 firms which supply at least one part used by” computer science” department
find all firms 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.
5. Do the operations balance customers? (, , , , , -, )
6. Under what condition is the following equation true ?
A1(R)= R
: means the number of tuples.
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