Given the following relational database schema (primary keys are bold and underlined). Answer questions 2.1 to 2.4:

branch(branch_id, branch_name, branch_city, assets)

customer(customer_id, customer_name, customer_street, customer_city, customer_st, customer_zip)

loan(loan_number, branch_id, amount)

borrower(customer_id, loan_number)

account(account_number, branch_id, balance)

depositor(customer_id, account_number)

2.1 List all possible foreign keys. For each foreign key list both the referencing and referenced relations.

2.2 Devise a reasonable database instance by filling the tables with data of your choice. Make sure to have at least 3 tuples in each table. Make sure that all tables exhibits entity integrity and referential integrity constraints. Make sure to use good table layout in your answer.

2.3 For each of the following queries, write a relational algebra expression to answer the query:

a) Find the names of all customers who live in Hopkins, and have the name Brewster.

b) Find the names and zip codes of all customers who have loans.

c) Find the names, cities of residence, and state for all depositors who have accounts with balance that is less than $3500

2.4 For each of the following relational algebra expressions, explain the output of the expression in words:

_{branch_name}(_{branch_city=chicago}( branch)

_{loan_number}(_{branch_name=mankato 1st ave}( branch loan)