MS VS2010 จะให้ฐานข้อมูลเก็บตัวเลข ตามจำนวนหลักที่เราต้องการ ทำอย่างไรครับ

OrderID DataType  = integer
OrderCode DataType  = (ISNULL(N'Fake'+ CONVERT(nvarchar(4), OrderID, 0), N'Error'))

OrderID   OrderCode
1              Fake1
2              Fake2
3              Fake3
...
...

USE [yourDB]
GO 
SET ANSI_NULLS ON
GO  100
SET QUOTED_IDENTIFIER ON
GO 1000

ALTER FUNCTION [dbo].[ufnLeadingZeros] (@Value INT)
RETURNS VARCHAR(4)
	WITH SCHEMABINDING
AS
BEGIN
	DECLARE @ReturnValue VARCHAR(8);

	SET @ReturnValue = CONVERT(VARCHAR(4), @Value);
	SET @ReturnValue = REPLICATE('0', 4 - DATALENGTH(@ReturnValue)) + @ReturnValue;

	RETURN (@ReturnValue);
END;

USE yourDB
GO
SET ANSI_NULLS ON
GO 100
SET QUOTED_IDENTIFIER ON
GO 1000
ALTER FUNCTION [dbo].[ufnLeadingZeros] (@Value INT)
RETURNS VARCHAR(4)
	WITH SCHEMABINDING
AS
BEGIN
	RETURN RIGHT(REPLICATE('0', 4) + LTRIM(@Value), 4);
END;

OrderID DataType  = integer
OrderCode DataType  = (ISNULL(N'' + [dbo].[ufnLeadingZeros](OrderID), N'Error'))

OrderID   OrderCode
1              0001
2              0002
3              0003
...
...

SELECT MAX(xTempField) + 1 AS OrderID
FROM (
	SELECT ROW_NUMBER() OVER (
			ORDER BY OrderCode
			) AS xTempField
	FROM yourTable
	) xTempTable