Access2003中使用 无限分类 模块函数，可用在查询中 类似SQL的存储过程

Access2003 中使用  无限分类 模块函数 ，可用在查询中

 Option Compare Database

'表结构 classid(int), parentid(int)  要求:两者都>0 且不相等 且 classid不能是自己和子孙节点
'生成查询后的结构 classid(int),parentid(int),ParentPath(string),ChildPath(string),Depth(int),Child(int)
'表查询中使用 SELECT ParentPath("newsClass",parentid) AS ParentPath, ChildPath("newsClass",classid) AS ChildPath,  Depth("newsClass",parentid) AS Depth, Child("newsClass",classid) AS Child, * FROM newsClass;


'--ParentPath 父类别路径
Public Function ParentPath(TableName As String, ParentId As Integer)
    Dim sPath As String
    Call getParentPath(TableName, ParentId, sPath)
    ParentPath = sPath
End Function

'--ChildPath 子类别路径
Public Function ChildPath(TableName As String, ClassId As Integer)
    Dim sPath As String
    Call getChildPath(TableName, ClassId, sPath)
    ChildPath = sPath
End Function

'--Depth 深度
Public Function Depth(TableName As String, ParentId As Integer)
    Dim iDepth As Integer
    iDepth = 0
    Call getDepth(TableName, ParentId, iDepth)
    Depth = iDepth
End Function

'--Child 子类别数量
Public Function Child(TableName As String, ClassId As Integer)
    Dim iChild As Integer
    iChild = 0
    Call getChild(TableName, ClassId, iChild)
    Child = iChild
End Function


'获取父路径 -- 递归法
'TableName :   表名,
'ParentId  :   父类别id
'sPath     :   父路径 (引用)  如: "0,1,5,9,10"
Function getParentPath(ByVal TableName As String, ByVal ParentId As Integer, ByRef sPath As String)
    Set rs = CurrentDb.OpenRecordset("select classid,parentid from " & TableName & " where classid = " & ParentId)
    If Not (rs.EOF) Then
        If (ParentId <> rs("parentid")) Then  '父类id 不能是自己
            Call getParentPath(TableName, rs("parentid"), sPath)
        End If
    End If
    If (sPath <> "") Then
        sPath = sPath & ","
    End If
    sPath = sPath & ParentId
    rs.Close
    Set rs = Nothing
End Function

'获取子路径 -- 递归法
'TableName :   表名,
'ClassId   :   当前类别id
'sPath     :   子类别路径 (引用) 如: "0,1,5,9,10"
Function getChildPath(ByVal TableName As String, ByVal ClassId As Integer, ByRef sPath As String)
    Set rs = CurrentDb.OpenRecordset("select classid,parentid from " & TableName & " where parentid = " & ClassId)
    Do While Not rs.EOF
        If (ClassId <> rs("classid")) Then  '子类id 不能是自己
            If (sPath <> "") Then
                sPath = sPath & ","
            End If
            sPath = sPath & rs("classid")
            Call getChildPath(TableName, rs("classid"), sPath)
        End If
        rs.MoveNext
    Loop
    rs.Close
    Set rs = Nothing
End Function

'获取深度 -- 递归法
'TableName :   表名,
'ParentId  :   父类别id
'iDepth    :   深度 (引用)
Function getDepth(ByVal TableName As String, ByVal ParentId As Integer, ByRef iDepth As Integer)
    Set rs = CurrentDb.OpenRecordset("select classid,parentid from " & TableName & " where classid = " & ParentId)
    If Not (rs.EOF) Then
        If (ParentId <> rs("parentid")) Then  '父类id 不能是自己
            iDepth = iDepth + 1
            Call getDepth(TableName, rs("parentid"), iDepth)
        End If
    End If
    rs.Close
    Set rs = Nothing
End Function

'获取孩子个数 -- 递归法
'TableName :   表名,
'ClassId   :   当前类别id
'iChild    :   孩子数量 (引用)
Function getChild(ByVal TableName As String, ByVal ClassId As Integer, ByRef iChild As Integer)
    Set rs = CurrentDb.OpenRecordset("select classid,parentid from " & TableName & " where parentid = " & ClassId)
    Do While Not rs.EOF
        If (ClassId <> rs("classid")) Then  '子类id 不能是自己
            iChild = iChild + 1
            Call getChild(TableName, rs("classid"), iChild)
        End If
        rs.MoveNext
    Loop
    rs.Close
    Set rs = Nothing
End Function