包含级别/距离列的闭包表 INSERT 语句

Question

我引用Bill Karwin's presentation 是为了实现一个有助于我管理层次结构的闭包表。不幸的是，演示文稿没有显示我如何插入/更新幻灯片 67 中提到的Level 列；这将非常有用。我一直在考虑，但我无法提出可以测试的具体内容。到目前为止，这是我得到的：

create procedure USP_OrganizationUnitHierarchy_AddChild 
    @ParentId UNIQUEIDENTIFIER,
    @NewChildId UNIQUEIDENTIFIER
AS
BEGIN
    INSERT INTO [OrganizationUnitHierarchy]
    (
        [AncestorId],
        [DescendantId],
        [Level]
    )
    SELECT [AncestorId], @NewChildId, (here I need to get the count of ancestors that lead to the currently being selected ancestor through-out the tree)
    FROM [OrganizationUnitHierarchy]
    WHERE [DescendantId] = @ParentId
    UNION ALL SELECT @NewChildId, @NewChildId
END
go 

我不确定我该怎么做。有什么想法吗？

Answer 1

您知道，对于 Parent = self，您的 Level = 0，当您从祖先复制路径时，您只是将 Level 增加 1：

create procedure USP_OrganizationUnitHierarchy_AddChild 
    @ParentId UNIQUEIDENTIFIER,
    @NewChildId UNIQUEIDENTIFIER
AS
BEGIN
    INSERT INTO [OrganizationUnitHierarchy]
    (
        [AncestorId],
        [DescendantId],
        [Level]
    )
    SELECT [AncestorId], @NewChildId, [Level] + 1
    FROM [OrganizationUnitHierarchy]
    WHERE [DescendantId] = @ParentId
    UNION ALL
    SELECT @NewChildId, @NewChildId, 0
END