SQL查詢獲取所需的DLL的所有依賴關係

Question

我試圖在Access數據庫中管理我的應用程序的依賴關係，並且我可以使用SQL查詢的幫助來讓我返回每個組件的列表作爲單個結果。

例如，假設我有一個附加列以下三個表未如下所示：

CurrentBuild  Versions   Dependencies 
============== ============== ======================================= 
Item Version Item Version Item Version Dependency DepVersion 
------ ------- ------ ------- ------ ------- ---------- ---------- 
MyExe 1.3  MyExe 1.0  MyExe 1.0  N/A   N/A 
MyDll1 1.0  MyExe 1.1  MyExe 1.1  N/A   N/A 
MyDll2 1.0  MyExe 1.2  MyExe 1.2  N/A   N/A 
MyDll3 1.1  MyExe 1.3  MyExe 1.3  N/A   N/A 
        MyExe 1.4  MyDll1 1.0  MyDll4  1.0 
        MyDll1 1.0  MyDll2 1.0  SomeMsDll 1.0 
        MyDll2 1.0  MyDll3 1.0  MyDll4  1.0 
        MyDll2 1.1  MyDll3 1.0  MyDll5  1.0 
        MyDll3 1.0  MyDll3 1.1  MyDll4  1.0 
        MyDll3 1.1  MyDll4 1.0  MyDll6  1.0 
        MyDll4 1.0  MyDll5 1.0  MyDll6  1.0 
        MyDll5 1.0  MyDll6 1.0  MyDll7  1.0 
        MyDll6 1.0  MyDll7 1.0  MyDll8  1.0 
        MyDll7 1.0 

我可以使用哪些查詢來獲取從CurrentBuild表下面的結果呢？我寧願對VBA宏進行簡單的查詢;然而，如果不能用查詢完成，我並不反對VBA宏。

Item  Version 
----------- ------- 
MyExe  1.3 
MyDll1  1.0 
MyDll2  1.0 
MyDll3  1.1 
MyDll4  1.0 
MyDll6  1.0 
MyDll7  1.0 
MyDll8  1.0 
SomeMsDll 1.0 

到目前爲止，我有以下，但這並不能給我想要的結果;它只是給我回CurrentBuild表的內容：

SELECT W.Item, W.Version 
FROM (SELECT DISTINCT V.[Item], V.[Version] 
    FROM ([Versions] AS V 
    INNER JOIN [Dependencies] AS D ON V.[Item] = D.[Dependency] AND V.[Version] = D.[DepVersion]) 
    INNER JOIN [CurrentBuild] AS S ON D.[Item] = S.[Item] AND D.[Version] = S.[Version] 

    UNION 

    SELECT DISTINCT V.[Item], V.[Item] 
    FROM [Versions] AS V 
    INNER JOIN [CurrentBuild] AS S ON V.[Item] = S.[Item] AND V.[Version] = S.[Version]) AS W; 

如果你很好奇，爲什麼MyExe沒有對MyDlls依賴關係，簡單的答案是，它並不需要回答關於這個問題我查詢;但是，僅供參考，這些DLL是動態加載的，所以MyExe對MyDll沒有構建時間依賴性。

謝謝。

Answer 1

包吸盤組成工會查詢，只要抓住每個項目的最高版本值：

SELECT Max(Item) as Item, Max(Version) as Version 
FROM 
(SELECT Item, Version 
FROM CurrentBuild 

UNION 

SELECT Item, Version 
FROM Versions 

UNION 

SELECT Item, Version 
FROM Dependencies 

UNION 

SELECT Dependency as Item, DepVersion as Version 
FROM Dependencies) AllItem 

GROUP BY Item, Version