====== Value provider for partner backend references ======

Backend references are used if a host system does not allow foreign referencing to the partner, e.g. no GLN numbers.

Until further notice, there are two special predefined value providers in eBiss3 to serve the backend references of the system or trading partners.
These are:
  - eBiss.TradingPartners.BackendId
  - eBiss.SystemPartners.BackendId

As soon as there are entries there, a backend reference can be selected at a respective system or trading partner **location**.

{{:images:sign_warning.png?nolink|}}**Note:** The backend reference selection can only be made on one location.

===== Application =====

As known eBiss usually needs an ID to determine the sender and receiver of a message.
In case that the host system only allows the own partner keys, these are entered in a value provider table and then assigned to the respective partner location data records.
Thus it is possible to make a correct assignment for both incoming and outgoing messages.

{{:images:sign_warning.png?nolink|}}**Note:** The following prerequisites apply to the use of the backend reference for partner recognition:
  - For OUTBOUND messages, the data element attribute **[[en:transformation:mappings:objektdefinition:attribute|MapFrameDocumentRecipient]]** or **[[en:transformation:mappings:objektdefinition:attribute|MapFrameDocumentSender ]]** is used on the INHOUSE objects and in the analyzer of the corresponding message type, the value **Anhand Backend Reference** is selected for the [[en:prozessdefinition:repositorien:analysator:partnererkennung|]].
  - For INBOUND messages, the [[en:transformation:mappings:funktionen:abfragefunktionen:lookup:tradingpartnerbackendreference]] function is used in the MIDDLEWARE on INHOUSE mapping to read the BackenReferenzID from the respective partner and pass it into the desired data element of the INHOUSE interface.