Hi Tanuj,
IBAN need not be always for vendors. It can be for our house bank accounts as well. If IBAN is generated with table name T012K, that means, this IBAN is related to our own house bank. In this case, key will have the combination of house bank+account ID. It can't have vendor number.
E.g: House bank = ABC
Account ID = EUR1
When you update house bank details with IBAN number,
Table name would be LFBK and table key would be ABC-EUR1. Table name and key are derived from where IBAN is generated. So, it need not be always vendor.
PS: What is your exact requirement? If it is to find IBAN of vendor, pass bank country, key and account (You can get these in LFBK) to TIBAN and get IBAN details. One vendor can have multiple bank accounts and hence multiple IBANs.
Please let us know if you need more information.
Thanks,
V V