Having a one to many AND many to many relationship between the same entities? Is it possible without using fluentAPI?

Question

Hello,

My Model:

    public class Bauteil {
        public Guid ID { get; set; }
        public string Name { get; set; }
 
        public Guid? BuildingID { get; set; } //FK to the main Building (optional if in archive only)
        public virtual Building Building { get; set; } 
 
        public virtual IList<Building> Buildings { get; set; } //List of Buildings used in
    }

    public class Building {
 
        public Guid ID { get; set; }
        public string Name { get; set; }
 
        public virtual IList<Bauteil> Bauteile { get; set; }
    }

fluent API

        protected override void OnModelCreating(DbModelBuilder modelBuilder) {
            modelBuilder.Entity<Building>()
                .HasMany<Bauteil>(building => building.Bauteile)
                .WithMany(bauteil => bauteil.Buildings);
        }

With this fluent API it is working.

Are there some naming conventions or attributes to have the same result without the fluentAPI?

I would really like having all the code in the Model itselfe... Because with the same Model classes I create many different Context Classes...

kind regards,

Markus

One more thing:

If I port the above working sample with the fluent API to my real project, where the Model is located in a different Assembly than the context I get the Error:

Schema specified is not valid. Errors:
(223,6) : error 0040: Type Anwesen_Bauteile is not defined in namespace MyTga.Web.DbContexts (Alias=Self).

(Where Type Anwesen = Type Building from the sampe code above)

(I use EF4.3)

Edited: The Problem for the error above is not the different Assembly but the fact that the Navigation property is in a base class

The following Model produces this error:

    public class Building {
 
        public Guid ID { get; set; }
        public string Name { get; set; }
 
        public virtual IList<Bauteil> Bauteile { get; set; }
        public virtual IList<Dokument> Dokumente { get; set; }
    }

    public class PartBase {
        public virtual IList<Building> Buildings { get; set; } //List of Building used in
    }

    public class Bauteil:PartBase {
        public Guid ID { get; set; }
        public string Name { get; set; }
 
        public Guid? BuildingID { get; set; } //FK to the main Building (optional if in archive only)
        public virtual Building Building { get; set; } 
 
    }

    public class Dokument:PartBase {
        public Guid ID { get; set; }
        public string Name { get; set; }
 
        public Guid? BuildingID { get; set; } //FK to the main Building (optional if in archive only)
        public virtual Building Building { get; set; }
 
    }

        protected override void OnModelCreating(DbModelBuilder modelBuilder) {
            modelBuilder.Entity<Building>()
                .HasMany<Bauteil>(building => building.Bauteile)
                .WithMany(bauteil => bauteil.Buildings);
            modelBuilder.Entity<Building>()
                .HasMany<Dokument>(building => building.Dokumente)
                .WithMany(dokument => dokument.Buildings);
        }

If I don't use PartBase as a base class it is working....

Answer 1

Hi M.Hopfenspirger,

Welcome!

Please refer my reply in this post: http://social.msdn.microsoft.com/Forums/en-US/adodotnetentityframework/thread/917b9207-17e8-4ee5-b33e-f621ef2a998a/

Have a nice day.

---

Alan Chen[MSFT]
MSDN Community Support | Feedback to us
Get or Request Code Sample from Microsoft
Please remember to mark the replies as answers if they help and unmark them if they provide no help.

Answer 2

Hi M.Hopfenspirger,

Sorry for missing your first question.

Using annotations for many to many as following:

public class Product
{
    [Key]
    public int Id { get; set; }
    [InverseProperty("Products")]
    public virtual ICollection<Category> Categories { get; set; }
}

public class Category
{
    [Key] 
    public int Id { get; set; }
    [InverseProperty("Categories")]
    public virtual ICollection<Product> Products { get; set; }
}

BTW, I'd like to check the states of your question.

Have a nice day.

---

Alan Chen[MSFT]
MSDN Community Support | Feedback to us
Get or Request Code Sample from Microsoft
Please remember to mark the replies as answers if they help and unmark them if they provide no help.

Answer 3

Hello Alan,

thanks for the reply. This is perfect :-)

Nice greetings, Markus