create table account
   (number 	varchar(15),
    branch_name		varchar(15)	not null,
    balance 		numeric		not null,
    primary key(number),
    foreign key(branch_name) references branch(name));

create table branch
   (name 	varchar(15),
    city 	varchar(15)	not null,
    assets 		numeric		not null,
    primary key(name));


create table customer
   (name 	varchar(15),
    street 	varchar(12)	not null,
    city 	varchar(15)	not null,
    primary key(name));

create table loan
   (number 	varchar(15),
    branch_name		varchar(15)	not null,
    amount 		numeric		not null,
    primary key(number),
    foreign key(branch_name) references branch(name));

create table depositor
   (customer_name 	varchar(15)	not null,
    account_number 	varchar(15)	not null,
    primary key(customer_name, account_number),
    foreign key(account_number) references account(number),
    foreign key(customer_name) references customer(name));

create table borrower
   (customer_name 	varchar(15)	not null,
    loan_number 	varchar(15)	not null,
    primary key(customer_name, loan_number),
    foreign key(customer_name) references customer(name),
    foreign key(loan_number) references loan(number));