Entity Framework Core creates unnecessary foreign key for owned type when using TPT mapping strategy

[vasicvuk]

File a bug

I found the original issue on Stackoverflow here:

https://stackoverflow.com/questions/75614840/entity-framework-core-creates-unnecessary-foreign-key-for-owned-type-when-using

I have the same issue, so I am pasting issue here:

When I configure any owned type in TPT child entity, ef creating additional foreign key to parent table. I have configuration like this:

modelBuilder.Entity<TransportBase>(e => {
  e.UseTptMappingStrategy();
  e.ToTable("transports");
})
modelBuilder.Entity<Car>(e => {
  e.OwnsOne(x => x.MaxSpeed, bld =>
  {
    bld.Property(x => x.Value)
      .UsePropertyAccessMode(PropertyAccessMode.Field)
      .HasColumnName("max_speed");
  });
  e.HasBaseType<TransportBase>();
  e.ToTable("cars"));
})

And it generates these constraints in table "cars":

constraints: table =>
                {
                    table.PrimaryKey("PK_cars", x => x.id);
                    table.ForeignKey(
                        name: "fk_cars_transports_id",
                        column: x => x.id,
                        principalTable: "transports",
                        principalColumn: "id",
                        onDelete: ReferentialAction.Cascade);
                    table.ForeignKey(
                        name: "fk_transports_transports_id",
                        column: x => x.id,
                        principalTable: "transports",
                        principalColumn: "id",
                        onDelete: ReferentialAction.Cascade);
                });

It is the same keys, except for the name. As far as I could figure it out, this is because the key for owned-type points to the primary key for Car. But the Id field flies into TransportBase, so ef starts thinking the owner is in another table and creates a foreign key. How can I fix it?

I tried to set shadow property, which will be principal key, but it creates unnecessary columns in table.

[AndriySvyryd]

Please try EF 9.0.0-preview.3.24172.4

If you are still experiencing the issue share a small runnable project that shows it.

[vasicvuk]

Hi @AndriySvyryd

We are using Entity Framework 8, is there also a fix for the EF Core 8 version? I didn't try EF 9 because I also use Oracle Devart driver which is not available for EF 9

[AndriySvyryd]

@vasicvuk Could you share a small runnable project that shows the issue? If possible, use the SqlServer provider

[vasicvuk]

Hi @AndriySvyryd I created a small repro on this repository: https://github.com/vasicvuk/ef-core-issue-33591

However i don't know if the issue is in EF Core or in EFCore.NamingConventions library because when UseCamelCaseNamingConvention is not used, everything works fine.

[AndriySvyryd]

This is indeed an issue in EFCore.NamingConventions. Same root cause as https://github.com/efcore/EFCore.NamingConventions/issues/191