I have come across blogs about how to setup an external content type (e.g. http://www.dotnetmafia.com/blogs/dotnettipoftheday/archive/2010/02/02/it-s-easy-to-configure-an-external-list-with-business-connectivity-services-bcs-in-sharepoint-foundation-2010.aspx) but I have not seen any examples of what to do when your external SQL DB has foreign keys.
For example. I have a database that has orders and customers. An order has one and only one customer and a customer can have many orders. How can I setup external content types in such a way that when in the list view of these external content types, I can jump between and possible lookup values to that other type?