我可以在分层数据模型中找到给定记录的所有子级(请参见下面的代码),但我不确定如何使用给定的子ID遍历回父/子链。有人能指点我如何做吗?在Linq to SQL中是否也可能实现这一点?
WITH TaskHierarchy (TaskID, [Subject], ParentID, HierarchyLevel, HierarchyPath) AS
(
-- Base case
SELECT
TaskID,
[Subject],
ParentID,
1 as HierarchyLevel,
CONVERT(VARCHAR(MAX),'/') AS HierarchyPath
FROM Task
WHERE TaskID = 2
UNION ALL
-- Recursive step
SELECT
t.TaskID,
t.Subject,
t.ParentID,
th.HierarchyLevel + 1 AS HierarchyLevel,
CONVERT(varchar(MAX),th.HierarchyPath + CONVERT(VARCHAR(32),t.ParentID) + '/') AS HierarchyPath
FROM Task t
INNER JOIN TaskHierarchy th ON
t.ParentID = th.TaskID
)
SELECT *
FROM TaskHierarchy
ORDER BY HierarchyLevel, [Subject]