MSSQL 無法修改資料庫TABLE結構問題? 已超過連接逾時的設定

我用SQL2005管理介面修改一個TABLE裡的欄位將varchar(20)改成varchar(60)， 一直無法改成功,請問該如何做?

Table約有100萬筆紀錄,錯誤訊息如下....... 
'Table_Name' 資料表 - 無法修改資料表。已超過連接逾時的設定。在作業完成之前超過逾時等待的時間，或者是伺服器未回應。

有人是這麼說的
To resolve this behavior, use one of the following methods:

•	Click to clear the Override connection string time-out value for table designer updates check box for the table designer and for the database designer in SQL Server Management Studio.
•	Specify a high setting in the Transaction time-out after box for the table designer and for the database designer in SQL Server Management Studio.
•	Modify the large table by using Transact-SQL statements in Query Editor in SQL Server Management Studio.

For more information about these settings, visit the following Microsoft Developer Network (MSDN) Web site:

http://msdn2.microsoft.com/en-us/library/ms188490.aspx

但我改了之後沒用，所以....自己寫SQL修改，成功了

 增加 Table 欄位

ALTER TABLE Table_Name
ADD 欄位名稱 nvarchar(4000)

修改 Table 屬性

ALTER TABLE Table_Name
ALTER COLUMN 欄位名稱 nvarchar(4000)