Question

I have two objects in my model

Car and carPart

with 1:n relationship.

I want to delete cascade the entity car.
when I delete i get the following exception :

 The operation failed: The relationship could not be changed because one or 
 more of the foreign-key properties is non-nullable. When a change is made 
 to a relationship, the related foreign-key property is set to a null value. 
 If the foreign-key does not support null values, a new relationship must 
 be defined, the foreign-key property must be assigned another non-null value, 
 or the unrelated object must be deleted.

I think it tries to delete the car object first and then the car parts.
Which is imposiible due to the foreign key.

How do I handle this ?
I want, obviously to delete the carPart first and then only the car.
Thanks.

Answer 1

You’ll need to tell the database that you want to cascade on delete, and then Entity Framework will do what you expect. You can change the FK behavior if you go to the Relationships screen for a table in SQL Server Management Studio: