## Types_of_banks

id | bank_type
--- | ---
1 | Central Bank
2 | Commercial Bank

## Countries

id | country_name
--- | ---
1 | USA
2 | UK

## Banks

id | name | type_id | country_id
--- | --- | --- | ---
|  | (→ Types_of_banks.id) | (→ Countries.id)
1 | Federal Reserve | 1 | 1
2 | Bank of England | 1 | 2
3 | Citibank | 2 | 1
4 | Barclays | 2 | 2

## Customers

id | first_name | last_name | birthdate | account_number | bank_id
--- | --- | --- | --- | --- | ---
|  |  |  | (→ Accounts.id) | (→ Banks.id)
1 | John | Doe | 1980-01-01 | 1 | 1
2 | Jane | Smith | 1985-05-15 | 2 | 2

## Accounts

id | balance | customer_id
--- | --- | ---
|  | (→ Customers.id)
1 | 1000.0 | 1
2 | 2000.0 | 2