text: create table if not exists saving_account(
      id serial primary key,
      bank_name text not null,
      branch text,
      account_number text not null unique,
      balance numeric(12,2) not null,
      constraint balance_non_negative check (balance >= 0),
      created_at timestamp not null default current_timestamp,
      modified_at timestamp not null default current_timestamp,
      active boolean not null default true
  );
  