I am using MVC 3, EF 4.1, and dbContext. I need to know how to delete an entity in one-to-many relation with a non-nullable foreign-key.
When I Remove the child entity
You can configure the relation to cascade ... this will propagate the delete to dependent entities.
But it's very dangerous :)
I prefer setting a flag in the row that prevents the data tier from including it in future queries, most applications do not need physical delete (and will be a chance to undo).