Flat hierarchyid in SQL Server 2008

在SQL Server 2008中引入了hierarchyid来处理树状结构。下面简单就以AdventureWorks(无hierarchyid)和AdventureWorks2008(有hierarchyid)里的HumanResources.Employee为例，来说明一下在新的hierarchyid中如何进行flat化的dimension抽取。
AdventureWorks是微软为SQL Server提供的数据库虚拟案例。
AdventureWorks中所要的结果集代码如下:
select L4.NationalIDNumber, L4.Title, L3.NationalIDNumber, L3.Title, L2.NationalIDNumber, L2.Title, L1.NationalIDNumber, L1.Title, L0.NationalIDNumber, L0.Title
from HumanResources.Employee L4, HumanResources.Employee L3, HumanResources.Employee L2, HumanResources.Employee L1, HumanResources.Employee L0
where L4.ManagerID = L3.EmployeeID and L3.ManagerID = L2.EmployeeID and L2.ManagerID = L1.EmployeeID and L1.ManagerID = L0.EmployeeID
AdventureWorks2008中的代码如下:
select L4.NationalIDNumber, L4.JobTitle, L3.NationalIDNumber, L3.JobTitle, L2.NationalIDNumber, L2.JobTitle, L1.NationalIDNumber, L1.JobTitle, L0.NationalIDNumber, L0.JobTitle
from HumanResources.Employee L0, HumanResources.Employee L1, HumanResources.Employee L2, HumanResources.Employee L3, HumanResources.Employee L4
where L4.OrganizationNode.GetAncestor(1)=L3.OrganizationNode and L3.OrganizationNode.GetAncestor(1)=L2.OrganizationNode and L2.OrganizationNode.GetAncestor(1)=L1.OrganizationNode and L1.OrganizationNode.GetAncestor(1)=L0.OrganizationNode
GetAncestor()是HierarchyNode类里其中的一个方法。更多hierarchyid数据类型方法引用可参考以下链接：
http://technet.microsoft.com/zh-cn/library/bb677193.aspx