根据 WBS 列新 PID 数据

之前写过关于菜单树的。 http://www.cnblogs.com/newsea/archive/2012/08/01/2618731.html

现在在写城市树。

结构：

CREATE TABLE [dbo].[S_City](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [Name] [varchar](50) NULL,
    [PID] [int] NULL,
    [Wbs] [varchar](50) NULL,
    [Code] [varchar](50) NULL,
    [SortID] [float] NULL,
    [IsValidate] [bit] NULL,
 CONSTRAINT [PK_City] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)  ON [PRIMARY]
) ON [PRIMARY]

用 Excel 导入了数据。数据是顺序树型的。 PID 是空的， Wbs 是正确的。顺序树的Wbs为： 1 ， 1.1 ， 1.2 ， 2 ， 2.1 ， 2.2 ，2.2.1 ，3 ，3.1 。。。。

需要做的工作：

1. 更新正确的 PID 。

2. 把WBS 更新为伪WBS，伪WBS 是 PWbs + "," + PID , 根节点的 WBS = PID

操作过程

用一个基础SQL，得到父PWbs，Level：

select *, 
SUBSTRING(wbs,1, LEN(wbs) - charindex('.', REVERSE( wbs) ) ) PWbs, 
LEN(wbs)- len(REPLACE(wbs,'.','')) as [Level]
from dbo.S_City
where LEN(wbs)- len(REPLACE(wbs,'.','')) = 1

再逐级更新PID

--第一步，更新根
update S_City
set pid = 0
where LEN(wbs)- len(REPLACE(wbs,'.','')) = 0

--第二步，更新二级：
update c
set c.pid = p.id
from S_City as c ,S_City as p
where  SUBSTRING(c.wbs,1, LEN(c.wbs) - charindex('.', REVERSE( c.wbs) ) ) = p.Wbs  and  LEN(c.wbs)- len(REPLACE(c.wbs,'.','')) = 1

--第三步，更新第三级

update c
set c.pid = p.id
from S_City as c ,S_City as p
where  SUBSTRING(c.wbs,1, LEN(c.wbs) - charindex('.', REVERSE( c.wbs) ) ) = p.Wbs  and  LEN(c.wbs)- len(REPLACE(c.wbs,'.','')) = 2

验证一下树：

with p as (
select * from S_City where Pid = 0
union all
select t.* from S_City as t join p on ( t.PID = p.ID)
)

select * from p

再更新 Wbs

--第一步，更新根
update S_City
set Wbs = '0'
where pid = 0

--第二步，更新二级：
update c
set c.Wbs = p.Wbs +',' + cast(p.id as varchar(30))
from S_City as c ,S_City as p
where  c.pid = p.ID and  p.PID = 0

--第三步，更新第三级

update c
set c.Wbs = p.Wbs +',' + cast(p.id as varchar(30))
from S_City as c ,S_City as p ,S_City as pp
where  c.pid = p.ID and  p.pid = pp.ID and  pp.PID = 0