Question

i’m with a trouble;

For initial imagine that we have an entity Member, and Member has Projects..

If you ask: Do projects have members? Yes they have…

Members (N*) <-> Project (N*) – so is a n-n-relationship.

But in my domain application i wanna say too that one Member is responsible for N projects, and one Project has one Member..

 public class Member : User
{
    public virtual ICollection<Project> ProjectsResponsable { get; set; }
    public virtual ICollection<Project> ProjectsWorker { get; set; }
}
public class Project
{
    public virtual int ProjectID { get; set; }
    public virtual String Name { get; set; }
    public virtual bool Enabled { get; set; }
    public virtual DateTime CreatedDate { get; set; }
    public virtual String Description { get; set; }

    public virtual Member Responsable { get; set; }
    public virtual ICollection<Member> Workers { get; set; }
    public virtual ICollection<Issue> Issues { get; set; }
}

For ProjectsWorker property in Worker will be a N-N relationship between Member and Project, but with this (the EF framework only creates for me the 1-way relashionship)

My question is… who can i a map these two relationships with code-first.
I was using DatabaseFirst, and now with code-first it appears to be very powerful but restrict me a little now.

Answer 1

You must tell EF which relationships belong together. You can do this either with data annotations …

public class Member : User
{
    [InverseProperty("Responsable")]
    public virtual ICollection<Project> ProjectsResponsable { get; set; }
    [InverseProperty("Workers")]
    public virtual ICollection<Project> ProjectsWorker { get; set; }
}

public class Project
{
    public virtual int ProjectID { get; set; }
    // ...
    [InverseProperty("ProjectsResponsable")]
    public virtual Member Responsable { get; set; }
    [InverseProperty("ProjectsWorker")]
    public virtual ICollection<Member> Workers { get; set; }
    // ...
}

(I believe the InverseProperty attribute is only necessary on one side of the relationship, but I am not sure.)

… or in Fluent API:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<Member>()
        .HasMany(m => m.ProjectsResponsable)
        .WithOptional(p => p.Responsable)  // or WithRequired(...)
        .WillCascadeOnDelete(false);

    modelBuilder.Entity<Member>()
        .HasMany(m => m.ProjectsWorker)
        .WithMany(p => p.Workers)
        .Map(a => {
            a.ToTable("MemberProjects");
            a.MapLeftKey("MemberID");
            a.MapRightKey("ProjectID");
        });
}