One to many relation with cascade giving error - entity-framework

Question

I am learning EF Code First with migrations, I have 3 entities :
[User] 1--->* [Call] 1--->* [ETA]
Code :
User.cs
public class User
{
[Key]
public int Id { get; set; }
public Guid LongId { get; set; }
[Required]
public string Name { get; set; }
public virtual ICollection<Call> Calls { get; set; } // many calls
public User()
{
LongId = Guid.NewGuid();
}
}
Call.cs
public class Call
{
[Key]
public int Id { get; set; }
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public string BreakdownNo { get; private set; }
[Required,MaxLength(32)]
public string Customer { get; set; }
[Required,MaxLength(32)]
public string TrailerNo { get; set; }
[Required, MaxLength(32)]
public string DepotContact { get; set; }
[Required, MaxLength(48), RegularExpression(#"^[_a-z0-9-]+(\.[_a-z0-9-]+)*#[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,4})$")]
public string DepotEmail { get; set; }
[Required, MinLength(9), MaxLength(32)]
public string DepotPhone { get; set; }
[Required, MaxLength(32)]
public string DriverContact { get; set; }
[Required, MinLength(9), MaxLength(32), RegularExpression(#"^(7\d{3}|\(?07\d{3}\)?)\s?\d{3}\s?\d{3}$")]
public string DriverPhone { get; set; }
[Required, MaxLength(256)]
public string LocatedAtFreeText { get; set; }
[Required, MaxLength(8), RegularExpression(#"^([A-PR-UWYZ0-9][A-HK-Y0-9][AEHMNPRTVXY0-9]?[ABEHMNPRVWXY0-9]? {0,1}[0-9][ABD-HJLN-UW-Z]{2}|GIR 0AA)$")]
public string LocatedAtPostCode { get; set; }
[Required, MaxLength(16)]
public string StartupNo { get; set; }
[Required]
public bool IsLoaded { get; set; }
[Required, MaxLength(256)]
public string FaultDescription { get; set; }
[Required]
public DateTime StartTime { get; set; }
public DateTime? EndTime { get; set; }
public string Status { get; set; }
public virtual User Controller { get; set; } // 1 controller
public virtual ICollection<ETA> ETAs { get; set; } // many ETAs
public Call()
{
StartTime = DateTime.Now;
ETAs = new List<ETA> { new ETA() };
Status = "Logged";
}
}
ETA.c
public class ETA
{
[Key]
public int Id { get; set; }
[Required]
public TimeSpan Value { get; set; }
public int CallId { get; set; }
public ETA()
{
Value = TimeSpan.FromMinutes(90);
}
}
I would like it so when I delete the User it deletes all of the Calls for the User, which in turn deletes all of the ETAs for those Calls.
When I delete a User row from the Database (using database explorer) it gives me an error :
No rows were deleted.
A problem occurred attempting to delete row 201.
Error Source: .Net SqlClient Data Provider.
Error Message: The DELETE statement conflicted with the REFERENCE constraint "FK_dbo.Calls_dbo.Users_Controller_Id". The conflict occurred in database "BreakdownDb", table "dbo.Calls", column 'Controller_Id'.

Answer 1

You can turn on the Cascade Delete option in Entity Framework, here you will find more info:
http://blogs.msdn.com/b/alexj/archive/2009/08/19/tip-33-how-cascade-delete-really-works-in-ef.aspx

Answer 2

The solution was to add OnModelCreating method to my DbContext class :
public class BreakdownDb : DbContext
{
public DbSet<Call> Calls { get; set; }
public DbSet<User> Users { get; set; }
public BreakdownDb(): base("name=DefaultConnection") {}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<User>().HasMany(x => x.Calls).WithRequired();
modelBuilder.Entity<Call>().HasMany(x => x.ETAs).WithRequired();
}
}