Documents in the business process are not independent of one another. For example, a request for a quotation is followed by a quotation and then a delivery. The need therefore arises for an overview of all the documents occurring in a business process or related in some other way. You also want to be able to jump back and forwards between such documents in the SAP System and also between many linked SAP Systems.

In addition, you want to know what type the relationships are which are between the individual documents. In the above example, this is "consists of" both times, whereby the offer occurs once in the role as the successor document and in the other occasion in the role of the preceding document. You therefore want to reduce the relationship to a simple model, through which time and causal connectivities between documents become apparent.

To reach these targets for any document, the object relationship service has been created. With this it is possible to link objects from the Business Object Repository (BOR) with one another. The relationships are modeled and are written by the application using the calling of a specific interface by the object relationship service API. All that the application has to transfer to this API is the Business Object from the BOR and the data from the object relationship model.