Hi, I am working on an application that works as follows: We have an entity "products" with some information attributes, and an entity "Order" My goal is to be able to create orders by selecting the available product objects. Therefore these entities have a many to many association (one product can be on multiple orders, and one order can contain multiple products). I now want to be able to add an order quantity to a product x in order y. So this quantity should be unique for the association between product x and order y. How can I do so? I already looked on the internet and came to the conclusion that I might need a helpentity, but how to add this in my domain model and how to use it, I am not sure. Any advice?