單表一對多關系很常見，它是一種樹形結構，如系統菜單表，部門表，分類表，這些都可以做成單表一對多關系，而這些表做成一對多關系后，如果通過EntityFramework進行插入操作時，會很方便，EF會自動為我們確實上級ID，對於操作的性能也是可以接受的，與數據庫建立一次鏈接，發一批指定，這是我們可以接受的，雖然在性能上不是最佳的，但綜合對比來看，它即是最佳的。（結合對比＝程序性能+開發人員工時+程序擴展性+程序可讀性）
OK，我們以菜單表為例，說一下這個菜單表初始化的過程
對於菜單實體的賦值，看一下代碼：
var menu = new WebManageMenus { About = string.Empty, LinkUrl = string.Empty, MenuLevel = 0, MenuName = form["MenuName"] ?? "根", Operator = string.Empty, ParentID = null, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now, WebManageMenus1 = new List<WebManageMenus> { new WebManageMenus { About = string.Empty, LinkUrl = string.Empty, MenuLevel = 1, MenuName ="系統管理", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now, WebManageMenus1 = new List<WebManageMenus> { #region 二級菜單 new WebManageMenus { About = string.Empty, LinkUrl = string.Empty, MenuLevel = 2, MenuName ="角色管理", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now, WebManageMenus1 = new List<WebManageMenus> { new WebManageMenus { About = string.Empty, LinkUrl = "/Role/Create", MenuLevel = 3, MenuName ="新建角色", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now }, new WebManageMenus { About = string.Empty, LinkUrl = "/Role/Index", MenuLevel = 3, MenuName ="管理角色", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now } } }, #endregion #region 二級菜單 new WebManageMenus { About = string.Empty, LinkUrl = string.Empty, MenuLevel = 2, MenuName ="部門管理", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now, WebManageMenus1 = new List<WebManageMenus> { new WebManageMenus { About = string.Empty, LinkUrl = "/Department/Index", MenuLevel = 3, MenuName ="管理部門", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now } } }, #endregion #region 二級菜單 new WebManageMenus { About = string.Empty, LinkUrl = string.Empty, MenuLevel = 2, MenuName ="菜單管理", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now, WebManageMenus1 = new List<WebManageMenus> { new WebManageMenus { About = string.Empty, LinkUrl = "/Menu/Index", MenuLevel = 3, MenuName ="管理菜單管理", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now } } }, #endregion #region 二級菜單 new WebManageMenus { About = string.Empty, LinkUrl = string.Empty, MenuLevel = 2, MenuName ="員工管理", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now, WebManageMenus1 = new List<WebManageMenus> { new WebManageMenus { About = string.Empty, LinkUrl = "/User/Create", MenuLevel = 3, MenuName ="新建員工", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now }, new WebManageMenus { About = string.Empty, LinkUrl = "/User/Index", MenuLevel = 3, MenuName ="管理員工", Operator = string.Empty, SortNumber = 1, Status = Status.Normal.GetHashCode(), UpdateDate = DateTime.Now } } }, #endregion } } } }; MenuRepository.Insert(menu);
我們可以看到，賦值的過程，我采用的EF生成的實體標准，對於子對象的賦值，我們可以看到,parentID並沒有賦值，因為這時它還沒不存在，這個parentID為上級
菜單的主鍵ID，所以EF在插入完父菜單后，會自動將ID賦值子對象的ParentID，這個過程是系統幫我們完成的。
對於上面的過程，所生成的SQL語句也是我們可以接受的
感謝您的閱讀，感謝Entity Framework開發團隊！