This necessary accounting is relatively simple and is rarely a problem for long-term projects. The idea is to define all the products in the agreement, which is why I added a list of. – Save on costs: Thanks to a long-term agreement with suppliers, you have special rates that can make a significant saving in the purchase budget Once an agreement has been concluded, individual purchases are granted to request the delivery of the products. The conditions can be a special price or a special delivery time. Since this information is currently stored on ProductSupplier, the idea is to implement a new matching criterion on the product supplier to determine that these lines only apply if the agreement is active. · As for scarcity, the seller of the buying organization ensures a reliable supply Why do you need such a link.