One-to-many: on insert from somewhere appears unknown column with EF core

Question

I have simple one-to-many relations.

public partial class LinkedDocument
{
    public Guid Id { get; set; }
    public Guid DocumentId { get; set; }

    public virtual TblDocumentData Document { get; set; }
}

public partial class TblDocumentData : IEntity<Guid>
{
    public Guid Id { get; set; }
    // other props
    public virtual ICollection<LinkedDocument> LinkedDocuments { get; set; } = new HashSet<LinkedDocument>();
}

modelBuilder.Entity<LinkedDocument>(
        entity =>
        {
            entity.ToTable("LinkedDocument");

            entity.HasKey(e => new {e.Id, e.DocumentId})
                  .HasName("PK_LinkedDocument")
                  .IsClustered(false);

            entity.Property(e => e.Id).ValueGeneratedNever();

            entity.HasOne(d => d.Document)
                  .WithMany()
                  .HasForeignKey(d => d.DocumentId)
                  .HasConstraintName("FK_LinkedDocument_TBL_DocumentData_DocumentId")
                  .IsRequired()
                  .OnDelete(DeleteBehavior.Cascade);
        });

and for TBL_DocumentData fluent api (only part)

entity.HasMany(d => d.LinkedDocuments)
                      .WithOne(d => d.Document)
                      .HasForeignKey(d => d.DocumentId)
                      .IsRequired();

On Save I have code like this:

this._ctx.Set<TblDocumentData>().Add(documentData);
this._ctx.Set<LinkedDocument>().Add(new LinkedDocument {Id = attachmentModel.EntityId, DocumentId = documentData.Id});
await this._ctx.SaveAsync(cancellationToken);

but on save I see error: Invalid column name 'TblDocumentDataId'. From debug console I can see that SQL script is generated like this:

INSERT INTO [LinkedDocument] ([DocumentId], [Id], [TblDocumentDataId])
      VALUES (@p22, @p23, @p24);

Searching by solution - cannot find column TblDocumentDataId - so this is something added by EF.

What I missed in configuration of my one-to-many relation?

Answer 1

Try changing entity.HasOne(d => d.Document).WithMany() to:

entity
    .HasOne(d => d.Document)
    .WithMany(data => data.LinkedDocuments) 

And you can remove the setup from entity.HasMany(d => d.LinkedDocuments) (I would argue that there is no point to setup the same twice).