Question

I have a structure of folders like this:

Folder1
  Folder1.1
  Folder1.2
Folder2
  Folder2.1
    Folder2.1.1
and so on..

The question is how to cascade delete them(i.e. when remove folder2 all children are also deleted). I can’t set an ON DELETE action because MSSQL does not allow it. Can you give some suggesions?

UPDATE: I wrote this stored proc, can I just leave it or it needs some modifications?

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

CREATE PROCEDURE sp_DeleteFoldersRecursive
    @parent_folder_id int
AS
BEGIN
    SET NOCOUNT ON;

    IF @parent_folder_id = 0 RETURN;

    CREATE TABLE #temp(fid INT );

    DECLARE @Count INT;

    INSERT INTO #temp(fid)
    SELECT FolderId FROM Folders WHERE FolderId = @parent_folder_id;

    SET @Count = @@ROWCOUNT;

    WHILE @Count > 0
    BEGIN
        INSERT INTO #temp(fid) 
            SELECT FolderId FROM Folders WHERE EXISTS
                   (SELECT FolderId  FROM #temp
                    WHERE Folders.ParentId = #temp.fid)
             AND  NOT EXISTS
                  (SELECT FolderId FROM #temp
                   WHERE Folders.FolderId = #temp.fid);    

             SET @Count = @@ROWCOUNT;         
    END

    DELETE Folders FROM Folders INNER JOIN #temp ON Folders.FolderId = #temp.fid; 
    DROP TABLE #temp;
END
GO

Answer 1

Normally it’s be a stored proc or INSTEAD OF trigger.

That is:

• generate your hierarchy of Folder2 from parameter/DELETED (recursive CTE approach for example))
• delete this hierarchy in one DELETE statement

The circular cascade/foreign key violations will not fire.