Entity Framework Core query left join not appears

Question

This is my DBContext

        modelBuilder.Entity<Solicitud>(entity =>
        {
            entity.Property(e => e.Id).ValueGeneratedNever();
            entity.HasOne(d => d.IdComentariosNavigation)
                .WithMany(p => p.Solicitud)
                .HasForeignKey(d => d.Id)
                .OnDelete(DeleteBehavior.ClientSetNull);
        });
         modelBuilder.Entity<SolicitudRevisionComentarios>(entity => 
        {
            entity.Property(e => e.id).ValueGeneratedNever();
            entity.Property(e => e.id_solicitud)
                .IsRequired()
                .HasMaxLength(4)
                .IsUnicode(false);

            entity.Property(e => e.motivo)
                .IsRequired()
                .HasMaxLength(300)
                .IsUnicode(false);

        });

this is my controller

  var result = new PagedCollectionResponse<SolicitudViewModel>();
  IEnumerable<Solicitud> items;
  items = _context.Solicitud.Include(p => p.IdEstatusNavigation).Include(p => p.IdComentariosNavigation).Where(p => p.Id == filterModel.Id);

And this is my models

 public partial class Solicitud : IAuditableEntity
 {
     public int Id { get; set; }
     public virtual SolicitudRevisionComentarios IdComentariosNavigation { get; set; }
 }

 public class SolicitudRevisionComentarios
 {
    public int id { get; set; }
    public int id_solicitud { get; set; }
    public string motivo { get; set; }
 }

The sql query I want to do is the next

 SELECT [p].*, [p.Comentarios].*, [p.Estatus].*
 FROM [Solicitud] AS [p]
 INNER JOIN [CatalogoEstatus] AS [p.Estatus] ON [p].[IdEstatus] = [p.Estatus].[Id]
 LEFT JOIN [SolicitudRevisionComentarios] AS [p.Comentarios] ON [p].[Id] = [p.Comentarios].[id]
 WHERE [p].[Id] = 666 --this is an example

But instead, the next query appears

 SELECT [p].*, [p.Comentarios].*, [p.Estatus].*
 FROM [Solicitud] AS [p]
 INNER JOIN [CatalogoEstatus] AS [p.Estatus] ON [p].[IdEstatus] = [p.Estatus].[Id]
 INNER JOIN [SolicitudRevisionComentarios] AS [p.Comentarios] ON [p].[Id] = [p.Comentarios].[id]
 WHERE [p].[Id] = 0 --this is an example

SolicitudRevisionComentarios is used when there is a value related to another table according to the id. If these id does not exist in SolicitudRevisionComentarios , return null. But i don´t all return to null query

This is an ASP.NET Entity Framework Core WebService with Microsoft .NET Core 2.2

Answer 1

The issue is that you are expecting a 1 to 0/1 relationship between Solictud and Comments, however your schema is 1 to many. What in your schema restricts more than one of your SolictudRevisionCommentario records having the same id_Solictud value?

For a Solictud to have only 1 Comment, it would need to form a many-to-1 relationship or a 1-to-0/1.

Many-to-1 would have a null-able SolictudRevisionCommentario ID on Solicitud.

1-to-0/1 would see id_Solictud to be the PK in the comment table.