Question

我正在创建一个包含自引用外键和hierarchyid的表。

是否有一种更简单的方法来填充hierarchyid，而不是为每个节点创建它，如下所示？

DECLARE @ID INT = 9

UPDATE  dbo.Tree
SET     Path = ( SELECT Path
             FROM   dbo.Tree
             WHERE  ID = 3).GetDescendant(( SELECT  PATH
                                            FROM    dbo.Tree
                                            WHERE   ID = @ID - 1
                                          ), NULL)
WHERE   ID = @ID

在此示例中，父节点具有ID 3，而8和9是3的子节点。

Answer 1

我现在能找到的最佳解决方案是将根节点设置为ParentID = -1，然后执行以下脚本。

DECLARE c1 CURSOR FOR (SELECT ID, ParentID FROM dbo.Tree WHERE ParentID != -1)

UPDATE dbo.Tree SET Path = NULL WHERE ParentID != -1

OPEN c1

DECLARE @ID INT, @ParentID INT

FETCH NEXT FROM c1 INTO @ID, @ParentID

WHILE @@FETCH_STATUS = 0
BEGIN

    UPDATE dbo.Tree SET Path = (SELECT Path FROM dbo.Tree WHERE ID = @ParentID).GetDescendant(
    (SELECT MAX(PATH) FROM dbo.Tree WHERE ParentID = @ParentID), NULL) WHERE ID = @ID

    FETCH NEXT FROM c1 INTO @ID, @ParentID
END

CLOSE c1
DEALLOCATE c1

在SQL 2008中自动创建HierarchyID

1 个答案: