A link for a specific exchange to a specific supplying dataset for that exchange as provided by the dataset author, as opposed to the links automatically added by the database service layer during linking of the system models.
In general, data providers do not need to supply activity links, since these are automatically added by the database service layer. However, if a specific group of enterprises are so closely linked in a supply chain that the production volumes of the specific suppliers can be shown to fluctuate with the demand of the specific customers, data providers shall add activity links to reflect this specific link.
The reason for linking directly to a specific supplying activity is provided in the comment field for the linked exchange. When transforming activities are linked directly, thus avoiding the market activities, the activities and data that are normally included with the market activities, are instead added directly to the activity requiring the input.