Entity Framework Core 3.0 Many-to-Many for the same table - entity-framework

Question

I am using ef core 3.0 code-first database. I have a table, Status, and I need to create a relationship to itself to list the possible "next status" List<Status> SubsequentStatuses. This is of course to systematically control the workflow of the object.
Using this at face value, it creates a one-to-many relationship and a new StatusId column in the table; however, I need to be able to set a status to be a "SubsequentStatus" to more than one Status.
For example, if there are 4 statuses:
New
In Work
Complete
Cancelled
I want to have the following
New
Subsequent Statuses
In Work
Cancelled
In Work
Subsequent Statuses
Complete
Cancelled
Complete
None
Cancelled
None
Notice that "Cancelled" is related to both "New" and "In Work"
Here are the classes and config that I have at this point:
public class EstimateStatus
{
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<EstimateStatusRel> SubsequentStatuses { get; set; }
}
public class EstimateStatusRel
{
public int EstimateStatusId { get; set; }
public EstimateStatus EstimateStatus { get; set; }
public int SubsequentStatusId { get; set; }
public EstimateStatus SubsequentStatus { get; set; }
}
public class SapphireContext : DbContext
{
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<EstimateStatusRel>().HasKey(x => new { x.EstimateStatusId, x.SubsequentStatusId });
modelBuilder.Entity<StatusRel>()
.HasOne(pt => pt.Status)
.WithMany(p => p.SubsequentStatuses)
.HasForeignKey(pt => pt.StatusId);
}
}
The issue this is creating, is that when Entity Framework is building the migration, it errors out about the multiple cascading delete action, but when I add the NoAction modifier to the modelBuilder fluent API, it still does not clear the error

Answer 1

It ended up being because I didn't specify an OnDelete action
This is my final config:
modelBuilder.Entity<EstimateStatusRel>()
.HasOne(pt => pt.Status)
.WithMany(p => p.SubsequentStatus)
.HasForeignKey(pt => pt.EstimateStatusId)
.OnDelete(DeleteBehavior.NoAction);

Answer 2

For self-reference in one-to-many relationships, you could try the below code:
public class EstimateStatus
{
public int Id { get; set; }
public string Name { get; set; }
public int? ParentId { get; set; }
public EstimateStatus ParentStatuses { get; set; }
public virtual ICollection<EstimateStatus> SubsequentStatuses { get; set; }
}
public class TestDbContext:DbContext
{
public TestDbContext (DbContextOptions<TestDbContext> options):base(options)
{ }
public DbSet<EstimateStatus> EstimateStatuse { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<EstimateStatus>()
.HasMany(e => e.SubsequentStatuses)
.WithOne(s => s.ParentStatuses)
.HasForeignKey(e => e.ParentId);
}
}