最近的专案使用这个功能，开发时为程序使用了就定了一个系统帐号如sa，由于某些要求，此帐号不能被更改或是删除，但用户可以添加其它帐号。可以参考下面动画。
实现这样的功能，也许方法有很多种。Insus.NET使用了SQL的触发器(Trigger)，在删除或是更新做了触发。
更新触发器，sa帐号不能被用户更新：
tri_Users_Update SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO -- ============================================= -- Author: Insus.NET -- Create date: 2012-03-03 -- Description: Disable update system account. -- ============================================= CREATE TRIGGER [ dbo ]. [ tri_Users_Update ] ON [ dbo ]. [ Users ] FOR UPDATE AS BEGIN IF @@ROWCOUNT = 0 RETURN SET NOCOUNT ON; DECLARE @UsersId INT, @Account NVARCHAR( 100) SELECT @UsersId = [ UsersId ] FROM deleted SELECT @Account = [ Account ] FROM inserted IF @UsersId = 1 and @Account <> N ' sa ' BEGIN RAISERROR(N ' 系统帐号，不能更新。 ', 16, 1) ROLLBACK TRANSACTION END END
删除触发器，sa帐号不能被用户删除。：
tri_Users_Delete SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO -- ============================================= -- Author: Insus.NET -- Create date: 2012-03-03 -- Description: Disable delete system account. -- ============================================= ALTER TRIGGER [ dbo ]. [ tri_Users_Delete ] ON [ dbo ]. [ Users ] FOR DELETE AS BEGIN IF @@ROWCOUNT = 0 RETURN SET NOCOUNT ON; DECLARE @UsersId INT, @Account NVARCHAR( 100) SELECT @UsersId = [ UsersId ], @Account = [ Account ] FROM deleted IF @UsersId = 1 OR @Account = ' sa ' BEGIN RAISERROR(N ' 系统帐号，不能删除。 ', 16, 1) ROLLBACK TRANSACTION END END