模仿参考:动易无限分类
优点:算得上是真正的无限分类，不过ParentPath是有局限性,ClassID是标识列自动增一.
缺点:新增过程中ParentID不存在还没有完善，会插入NULL数据.后面三个存储过程还在测试。
if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[ArticleClass]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [dbo].[ArticleClass]
GO
CREATE TABLE [dbo].[ArticleClass] (
[ClassID] [int] IDENTITY (1, 1) NOT NULL ,
[ClassName] [nvarchar] (100) COLLATE Chinese_Taiwan_Stroke_CI_AS NULL ,
[ParentID] [int] NULL ,
[ParentPath] [nvarchar] (255) COLLATE Chinese_Taiwan_Stroke_CI_AS NULL ,
[Depth] [int] NULL ,
[RootID] [int] NULL ,
[Child] [int] NULL ,
[PrevID] [int] NULL ,
[NextID] [int] NULL ,
[OrderID] [int] NULL
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[ArticleClass] ADD
CONSTRAINT [DF_ArticleClass_ParentID_65E11278] DEFAULT (0) FOR [ParentID],
CONSTRAINT [DF_ArticleClass_Depth_66D536B1] DEFAULT (0) FOR [Depth],
CONSTRAINT [DF_ArticleClass_RootID_67C95AEA] DEFAULT (0) FOR [RootID],
CONSTRAINT [DF_ArticleClass_Child_68BD7F23] DEFAULT (0) FOR [Child],
CONSTRAINT [DF_ArticleClass_PrevID_69B1A35C] DEFAULT (0) FOR [PrevID],
CONSTRAINT [DF_ArticleClass_NextID_6AA5C795] DEFAULT (0) FOR [NextID],
CONSTRAINT [DF_ArticleClass_OrderID_6B99EBCE] DEFAULT (0) FOR [OrderID],
CONSTRAINT [PK_ArticleClass] PRIMARY KEY CLUSTERED
(
[ClassID]
) ON [PRIMARY]
GO
exec sp_addextendedproperty N'MS_Description', N'主键', N'user', N'dbo', N'table', N'ArticleClass', N'column', N'ClassID'
GO
exec sp_addextendedproperty N'MS_Description', N'类别名称', N'user', N'dbo', N'table', N'ArticleClass', N'column', N'ClassName'
GO
exec sp_addextendedproperty N'MS_Description', N'父类ID', N'user', N'dbo', N'table', N'ArticleClass', N'column', N'ParentID'
GO
exec sp_addextendedproperty N'MS_Description', N'父类路径', N'user',
