EF6 Conflicting changes detected on save

Question

I have a parent/child hierarchy of which I want to insert a new parent into a DbContext and have it automatically persist the child objects.

Every time I all SaveChanges on DbContext EF is throwing an exception of

Conflicting changes detected. This may happen when trying to insert multiple entities with the same key.

I understand the error as the Child object doesn't have a Identity column.

Models are as follows:

public class Parent
{
     public int ParentId { get; set; }
     public string Name { get; set; }
     public ICollection<Child> Children { get; set; }
}

public class Child
{
     public int ParentId { get; set; }
     public virtual Parent Parent { get; set; }
     public string Name { get; set; }
}

Mapping for the Child object below::

public class ChildMap : EntityTypeConfiguration<Child>
{
   this.HasKey(p => p.ParentId);
   this.Property(p => p.ParentId)
       .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);

   this.HasRequired(t => t.Parent)
       .WithMany(t => t.Children)
       .HasForeignKey(d => d.ParentId);
}

The models were generated using EF Power tools as we are following DB-First design.

Is there a way saving the graph instead of saving the parent first then child?

If a parent can have multiple childs, you can't have ParentId as the primary key. — ESG, May 09 '15 at 02:40
The primary key is the foreign key (ParentId). There's no Identity column though — gnaungayan, May 09 '15 at 02:43
You cannot have multiple childs with the same primary key. It has to be unique. That's why you have the conflict. — ESG, May 09 '15 at 02:45
I missed something on the model and its working fine now. Thanks for the help — gnaungayan, May 09 '15 at 03:09
You missed what? I have the same problem, and your answer is far from helpfull. — MrKekson, Aug 03 '15 at 13:51

XtraSimplicity · Answer 1 · 2015-12-11T01:49:05.400

I had a similar issue, which was resolved by removing unnecessary FK associations from the Model. For some reason, these weren't removed when updating the model from the database.

To do this, I simply found the association in the Entity Designer, removed it, and re-updated the model from the database.

It can also be caused by having invalid relationship multiplicities on a particular column, i.e. a 0..1 - 1 relationship, rather than * - 1. Create a new Entity Diagram under the Model Browser and add the tables you're investigating (and their related tables), and you'll be able to easily see (and change) the multiplicities.

EF6 Conflicting changes detected on save

1 Answers1