Types_of_banks

idbank_type
1Central Bank
2Commercial Bank

Countries

idcountry_name
1USA
2UK

Banks

idnametype_idcountry_id
(→ Types_of_banks.id)(→ Countries.id)
1Federal Reserve11
2Bank of England12
3Citibank21
4Barclays22

Customers

idfirst_namelast_namebirthdateaccount_numberbank_id
(→ Accounts.id)(→ Banks.id)
1JohnDoe1980-01-0111
2JaneSmith1985-05-1522

Accounts

idbalancecustomer_id
(→ Customers.id)
11000.01
22000.02