Answer to Question #233927 in Computer Networks for upcoming legend

Question

2.1 Assuming the following relations from a customer database, write relational algebra expression
for each statement using symbolic notations.

Customer (cid, cname, rating, salary)
Item (iid, iname, type)
Order (cid, iid, day, qty)

2.1.1 Find the names of customers who have ordered item with id 087. (2)
2.1.2 Find the names of customers who have ordered a television i.e., an item of type television. (3)

Answer 1

(1)Find the names of customers who have ordered item with id 087.

Customer ⋈θ customer.cid=order.cid Order

(2)Find the names of customers who have ordered a television i.e., an item of type television.

Customer ⋈θ customer.cid=order.cid Order (Order order.iid=item.iid Item)