Entity Framework and MVC 3: The relationship could not be changed because one or more of the foreign-key properties is non-nullable

Question

I have been trying to use one View for updating an object and all its child collections (based on one-to-many relationships in an SQL Server database with an Entity Framewor

Answer 1

It looks like there is a Parent entity that has a one to many relationship with your Consultant entity. When you change an attribute of the Consultant entity that is used as the ForeignKey for that relationship, Entity Framework sets the relevant field in the Parent entity to null to decouple the relationship. When that field is not nullable you'll get this error. Actually that error definition is surprisingly good, I've seen this problem with far more cryptic errors.

So, I recommend that you check the parent entity in the database, and proceed to a remedy from there (if you can change it to nullable all is well, if it is part of a different constraint -pk or suchlike- you'll have to fiddle with your object models). I'd ask you to post your entity models, but the chunk of text is intimidating as it is.