Solution

For the following solution we use a simple bank account implementation. You can also make it more specific as described in MODELLING_BANK_ACCOUNTS.

Schema

The diagram can also be found online on dbdiagram.io.

Table article {
  id integer [not null, unique]
  number integer [not null, unique]
  name char(255) [not null]
  amount integer [not null]
  reorder_point integer [not null]
}

Table supplier {
  id integer [not null, unique]
  name char(255) [not null, unique]
  street char(255) [not null]
  city char(255) [not null]
  // ZIP code in USA is 10 characters max
  // @see https://www.oreilly.com/library/view/regular-expressions-cookbook/9781449327453/ch04s14.html
  zip char(10) [not null]
}

Table account {
  id integer [not null, unique]
  iban char(34) [not null, unique]
  supplier_id integer [not null, ref: > supplier.id]
  bank_id integer [not null, ref: > bank.id]
}

// bank can be identified by the IBAN
Table bank  {
  id integer [not null, unique]
  name char(255) [not null, unique]
  // @see https://en.wikipedia.org/wiki/ISO_9362
  bic char(11) [not null, unique]
}

Table article_in_supplier {
  id integer [not null, unique]
  article_id integer [not null, ref: > article.id]
  supplier_id integer [not null, ref: > supplier.id]
  price decimal(6,2) [not null]
}