Nullable Foreign Key bad practice?

Question

Let\'s say you have a table Orders with a foreign key to a Customer Id. Now, suppose you want to add an Order without a Customer Id, (whether that should be possible is anot

Answer 1

You could always add an artificial row to your Customer table, something like Id=-1 and CustomerName = 'Unknown' and then in cases when you would normally set your CustomerId in Order NULL set it to -1.

This allows you to have no nullable FKs but still represent the lack of data appropriately (and will save you from downstream users not knowing how to deal with NULLs).