在 Entity Framework Core 中播种关系数据

Question

I've found several SO posts on this but can't identify what I'm doing wrong here.

I'm trying to seed two tables with an item each. The second item contains a lookup to the first. I can seed the parent with no issue, but cannot figure out the correct syntax to seed the child.

Here is the code I use to seed the parent

   modelBuilder.Entity<Group>().HasData(new Group
        {
            Id = 1,
            Name = "Any",
            IsDeleted = false
        });

And here is the code to seed the child - this fails:

 modelBuilder.Entity<ShiftTypeDb>().HasData(new 
        {
            Id = 1,
            Name = "Any",
            GroupId = 1,

            IsDeleted = false
        });

Following the advice from the docs I've used an anonymous object instead of the class itself. I've also tried using the navigation property and both the foreign key and the nav prop at the same time. The Group with id=1 is definitely in the db already so it isn't a question of the parent item not existing.

The error message I get is:

Insert or update on table "shifttypes" violates foreign key constraint "fk_shifttypes_groups_groupid"

And the SQL generated for the seed is

INSERT INTO shifttypes (id, groupid, isdeleted, name)
VALUES (1, 0, FALSE, 'Any');

It is clearly inserting a '0' as the GroupId, despite it being hardcoded as '1' in the seed; I cannot figure out why this is the case. Below is the code for the two entities that represent these two tables:

public class Group
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsDeleted { get; set; }
    public ICollection<ApplicationUser> Users { get; set; }

    public Group()
    {
    }

    public Group(string name)
    {
        Name = name;
    }
}

public class ShiftTypeDb
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsDeleted { get; set; }
    public int GroupId { get; set; }
    public Group Group { get; set; }

    public ShiftTypeDb()
    {
    }
}

Answer 1

This code was tested in Visual Studio and worked properly. After fixing all bugs you have to delete existing db and migration and create the new one using Add-Migration InitialCreate option.

You have one-to-one relation instead of one-to-many. To fix the bug add ShiftTypeDb collection to the Group class:

    public class Group
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsDeleted { get; set; }
    public virtual ICollection<ApplicationUser> Users { get; set; }

    public virtual ICollection<ShiftTypeDb> ShifTypeDbs { get; set; }

   ...other properties
}

ans use ShiftTypeDb instead of anonymous type. Anonymous types are used only if your class have shadow properties. And be sure that group is ahead of TypeDB

modelBuilder.Entity<ShiftTypeDb>(
                entity =>
                {
                    entity.HasOne(d => d.Group)
                        .WithMany(p => p.ShiftTypeDbs)
                        .HasForeignKey("GroupId");
                });
 

modelBuilder.Entity<ShiftTypeDb>().HasData(new ShiftTypeDb 
        {
            Id = 1,
            Name = "Any",
            GroupId = 1,
            IsDeleted = false
        })