Entity Framework Code First One to One With Cascade Delete

Tuesday, September 3, 2013

I recently had to figure how to achieve cascade deletes on a one to one mapping. The solution, I soon found out, required fluent configuration.

Here’s some simple entities:

public class Principal

{

    public Int32 PrincipalId { get; set; }

    public virtual Detail Detail { get; set; }

    //other properties go here

}

  

public class Detail

{

    [Key]

    [ForeignKey("Principal")]

    public Int32 PrincipalId { get; set; }

    [Required]

    public Principal Principal { get; set; }

    //other properties go here

}

The fluent configuration needs to be:

protected override void OnModelCreating(DbModelBuilder modelBuilder)

{

    modelBuilder.Entity<Principal>().HasOptional(x => x.Detail).WithRequired(x => x.Principal).WillCascadeOnDelete(true);

 

    base.OnModelCreating(modelBuilder);

}