CREATE TABLE [dbo].[myTable](
	[ID] [int] IDENTITY(1,1) NOT NULL,
	[title] [varchar](255) NOT NULL,
	[parentID] [int] NULL,
 CONSTRAINT [PK_myTable] PRIMARY KEY CLUSTERED 
(
	[ID] ASC
)WITH (PAD_INDEX  = OFF, IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
 

 
SET IDENTITY_INSERT myTable ON
GO
 
INSERT INTO myTable(ID, title, parentID) VALUES(1,'Microsoft', NULL)
INSERT INTO myTable(ID, title, parentID) VALUES(2,'C#', 1)
INSERT INTO myTable(ID, title, parentID) VALUES(3,'VB.net', 1)
INSERT INTO myTable(ID, title, parentID) VALUES(4,'Open Source', NULL)
INSERT INTO myTable(ID, title, parentID) VALUES(5,'Python',	4)
INSERT INTO myTable(ID, title, parentID) VALUES(6,'Ruby', 4)
INSERT INTO myTable(ID, title, parentID) VALUES(7,'PHP', 4)
INSERT INTO myTable(ID, title, parentID) VALUES(8,'Perl', 4)
INSERT INTO myTable(ID, title, parentID) VALUES(9,'Java', 4)
INSERT INTO myTable(ID, title, parentID) VALUES(10,'LinQ', 2)
INSERT INTO myTable(ID, title, parentID) VALUES(11,'5.2', 7)
INSERT INTO myTable(ID, title, parentID) VALUES(12,'4.4', 7)
 
GO
SET IDENTITY_INSERT myTable OFF
GO
 

 
CREATE PROCEDURE viewMyTable
AS
BEGIN
	SELECT ID, title, ISNULL(parentID, 0) AS parentID
	FROM myTable
END
 

 
ALTER TABLE [dbo].[myTable]  WITH CHECK ADD  CONSTRAINT [FK_myTable_myTable] FOREIGN KEY([parentID])
REFERENCES [dbo].[myTable] ([ID])
GO
ALTER TABLE [dbo].[myTable] CHECK CONSTRAINT [FK_myTable_myTable]
 

 
protected void PopulateTreeView (TreeNodeCollection parentNode, int parentID, DataTable folders)
{   
    foreach (DataRow folder in folders.Rows)
    {
        if (Convert.ToInt32(folder["parentID"]) == parentID)
        {
            String key = folder["ID"].ToString();
            String text = folder["title"].ToString();
            TreeNodeCollection newParentNode = parentNode.Add(key, text).Nodes;
            PopulateTreeView(newParentNode, Convert.ToInt32(folder["ID"]), folders);                    
        }
    }
}