DBMS Korth Edition 6 Exercise 2 Question 8 (Page No. 54)

Question

Consider the bank database given below. Give an expression in the relational
algebra for each of the following queries.
a. Find the names of all branches located in “Chicago”.
b. Find the names of all borrowers who have a loan in branch “Downtown”.

branch(branch name, branch city, assets)
customer (customer name, customer street, customer city)
loan (loan number, branch name, amount)
borrower (customer name, loan number)
account (account number, branch name, balance)
depositor (customer name, account number)

Answer 1

1) $\sqcap_{branch name} (\sigma _{branch city= chicago}(branch)))$

2) π customer_name ($\sigma _{branch name="downtown")}(borrower \bowtie loan)$