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EF CF Many to Many and One to Many together RRS feed

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    I've done research about that, but I didn't find any solution. I'm using SQL CE 4.0 and I want to make relations like:

    public class Process
{
   [Key]
   public int Id {get;set;}
   public string Name {get; set;}
   public int CurrentStageID {get;set;}

   [ForeignKey("CurrentStageID")]
   public virtual Stage CurrentStage {get;set;}

   public virtual ICollection<Stage> Stages {get;set;}
}

public class Stage
{
   [Key]
   public int Id {get;set;}
   public string Name {get; set;}
   public int ProcessId {get;set;}

   [ForeignKey("ProcessId")]
   public virtual Process Process {get;set;}
}

    But during database initialization I get Exception:

    The referential relationship will result in a cyclical reference that is not allowed. [ Constraint name = FK_dbo.Stages_dbo.Processes_ProcessId ]

    Such relation is correct?

    I also use OnModelCreating() method:

    modelBuilder.Entity<Process>()
     .HasMany(p=>p.Stages)
     .WithRequired(s=>s.Process)
     .HasForeignKey(s=>s.ProcessId);

    Anyone can help me with that?

    AD. If I add .WillCascadeOnDelete(false); I get:

    One or more validation errors were detected during model generation:

    SQLCEEngine.Proces_Etapy: : Multiplicity conflicts with the referential constraint in Role 'Process_Stages_Source' in relationship 'Process_Stages'. Because all of the properties in the Dependent Role are non-nullable, multiplicity of the Principal Role must be '1'


    Monday, June 23, 2014 10:27 AM

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    Hello,

    I am confused since you are trying to build the many to many relationship, I don’t see that there is a collection type in your Stage entity class. Here, with your model, I change it a little and it could create a many to many and one to many relationships together as:

    public class Sample20140624Context : DbContext

    {

        public DbSet<Process> Processes { get; set; }

        public DbSet<Stage> Stages { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)

        {

            modelBuilder.Entity<Process>().Property(p => p.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);


            modelBuilder.Entity<Stage>().Property(s => s.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.None);


            modelBuilder.Entity<Process>().HasMany(s => s.Stages).WithMany(s => s.Processes);


            modelBuilder.Entity<Process>().HasRequired(s => s.CurrentStage).WithMany(s => s.Processes).HasForeignKey(p => p.CurrentStageID).WillCascadeOnDelete(false);

        }

    }


    public class Process

    {

        public int Id { get; set; }

        public string Name { get; set; }

        public int CurrentStageID { get; set; }

        public virtual Stage CurrentStage { get; set; }

        public virtual ICollection<Stage> Stages { get; set; }

    }


    public class Stage

    {

        public int Id { get; set; }

        public string Name { get; set; }

        public virtual ICollection<Process> Processes { get; set; }

        public virtual ICollection<Process> ProcessForMany { get; set; }

    }

    The relationship is shown as:

    You can have a try and if I misunderstand, please let me know.

    Regards.

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    • Marked as answer by Fred Bao Wednesday, July 2, 2014 3:34 AM
    Tuesday, June 24, 2014 7:23 AM