Entity Framework Core 中的种子脚本正在破坏我的迁移

Question

I have a very simple scenario where I have number of related entities and a couple of them are expected to be prefilled (through seed script). Then, I run my application and it adds a new related data (related to the tables populated by seed script).

And eventually, when I want to add a new migration, for example make a field nullable (of an entity which was not seeded), I try the update-database command and everything breaks up because the migration is trying to recreate my seeded tables. It is impossible because they keep a foreign key.

I will be more specific:

Car (Id, Brand, Color, Year)

many-to-one

CarType (Id, Value)

So, in my DbContext I have the following:

modelBuilder.Entity<CarType>()
                .HasData(new CarType('4125ad9e-68fe-4d25-9d73-7e8acc097d6f', 'Coupe'))

And then, I run my application and I start inserting new Car s with the respective types. So, now I have:

Car(1, 'BMW', 'Black', 2011) FK-> CarType('4125ad9e-68fe-4d25-9d73-7e8acc097d6f', 'Coupe')
Car(2, 'Audi', 'Green', 2008) FK-> CarType('cc097d6f9e-68fe-4d25-9d73-4125ad7e8a', 'Estate')

But, one day I decide to make the Year field nullable

public int? Year { get; set; }

I ran add-migration and everything looks fine except for that in the Up statement:

migrationBuilder.DeleteData(
                table: "CarType",
                keyColumn: "Id",
                keyValue: new Guid("4125ad9e-68fe-4d25-9d73-7e8acc097d6f"));

Once I execute update-database I get an error that the operation can not be executed because there's a foreign key related to the entity I am trying to delete:

The DELETE statement conflicted with the REFERENCE constraint

How am I supposed to handle that? My seed scrips are kind of blocking me right now. I want to be able to make changes to my other tables, even on the ones that are seed scripted without the need to recreate stuff.

Answer 1

I think you've records in DB depends on Card Type Id with the same Id you tried to delete so you can manually delete all dependent entities from DB then apply update database and this not recommended or change all entities that have relation with CardType to be "Cascade" in onModelCreating function

example

entity.HasOne(d => d.CardTypes)
                .WithMany(p => p.Cards)
                .HasForeignKey(d => d.CardTypeId)
                .OnDelete(DeleteBehavior.Cascade)   /* Cascade */
                .HasConstraintName("FK_Cards_CardTypes");

Answer 2

The solution for me was to remove the HasData related seeding from my DbContext because when a migration is added the changes to the data specified with HasData are transformed to calls to InsertData (), UpdateData (), and DeleteData ().

So, as suggested HERE , I moved the initialization logic into my initial migration.

migrationBuilder.InsertData(
    table: "CarType",
    columns: new[] { "Id", "Value" },
    values: new object[] { "4125ad9e-68fe-4d25-9d73-7e8acc097d6f", "Coupe" });