Entity Framework setting navigation property null in zero to one association

Question

I have a Zero to one association between two tables. For instance, I have entity Car and Entity License and a car can have 0 or 1 License.
(A car can have one license, but a license can have 0 or 1 car) When I try to remove a car's license, by setting Car.License = null i get an exception such as:

A relationship from the 'Car_Licence' AssociationSet is in the 'Deleted' state. Given multiplicity constraints, a corresponding 'License' must also in the 'Deleted' state.

I want the license to stay in the main Licenses DbSet, and i want it's reference to Car to remain, all I want it that the Car's license be set to null.

What am i missing?

Answer 1

Setting Car.License to null conflicts with association you have set, where car must have one license set. You need to change your association so that car can have one or zero licenses for it to work.

EDIT

You will have to set both ends of association to zero or one if you want to null the property.