当Child具有WillCascadeOnDelete的外键时，实体框架无法删除父条目（false）

Question

Why I cannot delete the parent entry while the child of it is set with WillCascadeOnDelete(false) on the foreign key?

This is the parent:

public class EA_Client
{
    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    [Display(Name = "Client Id")]
    public int ClientId { get; set; }

    [Display(Name = "User Id")]
    public int? UserId { get; set; }

    [Display(Name = "Client Name")]
    public string ClientName { get; set; }

    public virtual AlvinCMSExtension.Models.UserProfile User { get; set; }

    public EA_Client()
    {
        UserId = 0;
        ClientName = "";
    }
}

This is the child :

public class EA_Order
{
    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    [Display(Name = "Order Id")]
    public int OrderId { get; set; }

    [Display(Name = "Client Id")]
    public int? ClientId { get; set; }

    [Display(Name = "Supplier Id")]
    public int? SupplierId { get; set; }

    [Display(Name = "Total Amount To Pay")]
    public decimal TotalAmountToPay { get; set; }

    [Display(Name = "Order Time")]
    [DataType(DataType.Date)]
    [DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
    public DateTime OrderTime { get; set; }

    [Display(Name = "Description")]
    public string Description { get; set; }

    public virtual ICollection<EA_OrderStatus> OrderStatuses { get; set; }
    public virtual ICollection<EA_OrderDetail> OrderDetails { get; set; }
    public virtual EA_Client Client { get; set; }
    public virtual EA_Supplier Supplier { get; set; }

    public EA_Order()
    {
        ClientId = null;
        SupplierId = null;
        TotalAmountToPay = 0;
        OrderTime = DateTime.Now;
        Description = "";
    }
}

This is the model builder for the child :

        mb.Entity<EA_Order>().HasOptional<EA_Client>(m => m.Client).WithMany().HasForeignKey(m => m.ClientId).WillCascadeOnDelete(false);
        mb.Entity<EA_Order>().HasOptional<EA_Supplier>(m => m.Supplier).WithMany().HasForeignKey(m => m.SupplierId).WillCascadeOnDelete(false);
        mb.Entity<EA_Order>().HasMany<EA_OrderStatus>(m => m.OrderStatuses);
        mb.Entity<EA_Order>().HasMany<EA_OrderDetail>(m => m.OrderDetails);

Everytime I tried to delete the parent (EA_Client), this error occurs :

{"The DELETE statement conflicted with the REFERENCE constraint \\"FK_EAccounting.EA_Order_EAccounting.EA_Client_ClientId\\". The conflict occurred in database \\"EAccountingDB\\", table \\"EAccounting.EA_Order\\", column 'ClientId'.\\r\\nThe statement has been terminated."}

How to fix this? I want to be able to delete the parent (EA_Client) since the parent is optional, means it is ok to have the child (EA_Order) to be orphanage entry.

Answer 1

I believe that WillCascadeOnDelete should be specified for parent entity, not for child. Also if dependency is optional (as you have) default behavior should be keeping children on parent removing. Did you try just remove your .WillCascadeOnDelete(false) and delete Client entity?

Update:

MSDN link to approve my statement.