Using a navigation property to clear a foreign key fails in 2.0.0

Given the following two (simplified) models, configured with the foreign key as DeleteBehavior.Restrict:

public class Asset
{
    public int Id { get; set; }
}

public class Product
{
    public int Id { get; set; }

    public int? DownloadAssetId { get; set; }
    public Asset DownloadAsset { get; set; }
}

Trying to clear the asset with product.DownloadAsset = null; (after loading the data with .Include(x => x.DownloadAsset)) results in the following error:

The association between entity types 'Asset' and 'Product' has been severed but the foreign key for this relationship cannot be set to null. If the dependent entity should be deleted, then setup the relationship to use cascade deletes.

Clearing with product.DownloadAssetId = null; works as expected.

Obviously I don’t want any entities to be deleted in this case; the only action I expect to occur is for the specified DownloadAssetId to be set to null.

It’s kind of difficult for me to test it now, but I’m pretty sure this worked as I expected in 1.1.x.

Further technical details

EF Core version: 2.0.0 Database Provider: Microsoft.EntityFrameworkCore.SqlServer Operating system: Windows 10 IDE: Visual Studio 2017 15.3

[svallis]

Thanks for the responses.

Question: why were you explicitly configuring Restrict in your 1.1.x code?

Bear in mind this code base has been around since pre 1.0.0. Some of the foreign keys were being created in my migrations with ReferentialAction.Cascade, which I didn’t want. I added the following in OnModelCreating():

// make referential delete behaviour restrict instead of cascade for everything
foreach (var relationship in builder.Model.GetEntityTypes().SelectMany(x => x.GetForeignKeys()))
{
    relationship.DeleteBehavior = DeleteBehavior.Restrict;
}

Commenting that out in 2.0.0 and generating a new migration is still trying to create ReferentialAction.Cascade relationships in places that I don’t want. Switching to the new DeleteBehavior.ClientSetNull is perfect though, many thanks!

[ajcvickers]

@svallis Thanks for the information. Glad it is working for you now. (FYI: relationships get cascade delete by convention when the FK is not nullable.)