如何优雅地检查存储过程的返回值

Here is my current implementation of a stored procedure which returns Order status for a given Order ID. There are two situations,

这是我当前的存储过程实现,它返回给定订单ID的订单状态。有两种情况,

there is matched Order ID and I will retrieve the related status,

有匹配的订单ID,我将检索相关的状态,

there is no matched Order ID (i.e. non-existing Order ID).

没有匹配的订单ID(即不存在的订单ID)。

My confusion is, how to implement the two functions elegantly/efficiently in one stored procedure, so that I return matched Order ID for situation 1 and also indicate client no matched Order ID in situation 2?

我的困惑是,如何在一个存储过程中优雅/高效地实现这两个功能,以便我返回情况1的匹配订单ID,并指出客户在情况2中没有匹配的订单ID?

I am using VSTS 2008 + C# + ADO.Net + .Net 3.5 as client, and using SQL Server 2008 as server.

我使用VSTS 2008 + C#+ ADO.Net + .Net 3.5作为客户端,并使用SQL Server 2008作为服务器。

CREATE PROCEDURE [dbo].[GetStatus] 
    @ID [nvarchar](256),
    @Status [int] output
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON; 

    -- Insert statements for procedure here 
    SELECT @Status = [Status] 
    FROM [dbo].[OrderStatus]        
    WHERE (@ID = [ID]);
END

thanks in advance, George

乔治,提前谢谢

3 个解决方案

#1

why are you using output parameter.

你为什么使用输出参数。

you just need to take your stored procedure result in dataset of the data access layer. just check that if (dataset != null) then take value else return appropriate message to your business layer.

您只需要将存储过程结果存入数据访问层的数据集中。只需检查if(dataset!= null)然后取值,否则返回适当的消息到您的业务层。

#2

There are multiple approaches you can take:

您可以采取多种方法:

Keep everything as is and in your .NET code, if the @status value returned is DBNull, then it will indicate situation 2, otherwise situation 1.

按原样和.NET代码保存所有内容,如果返回的@status值为DBNull,则表示情况2,否则情况为1。
Add a RETURN statement to the SPROC and use

将一个RETURN语句添加到SPROC并使用

Dim returnValue As New SqlParameter("@RETURN_VALUE", SqlDbType.Int)

Dim returnValue As New SqlParameter(“@ RETURN_VALUE”,SqlDbType.Int)

returnValue.Direction = ParameterDirection.ReturnValue

returnValue.Direction = ParameterDirection.ReturnValue

Cmd.Parameters.Add(returnValue)

in your .NET code to explicitly identify what the SPROC returned and take action accordingly.

在您的.NET代码中明确标识SPROC返回的内容并相应地采取措施。

As an additional tip, use a SET instead of SELECT when assigning the value to @Status variable in the SPROC. This will guarantee that you get a NULL back if there is no match found. So,

作为附加提示,在SPROC中将值赋给@Status变量时,请使用SET而不是SELECT。如果找不到匹配项,这将保证您返回NULL。所以,

` -- Insert statements for procedure here

` - 在此插入程序语句

SET @Status = SELECT [Status] 
FROM [dbo].[OrderStatus]            
WHERE (@ID = [ID]);`

#3

You can use the "if statements" inside the stored procedures. the web site at bottom gives you some tips.

您可以在存储过程中使用“if语句”。底部的网站为您提供了一些提示。

http://translate.google.com.br/translate?u=http%3A%2F%2Fmail.firebase.com.br%2Fpipermail%2Flista_firebase.com.br%2F2005-November%2F021883.html&sl=pt&tl=en&hl=pt-BR&ie=UTF-8

#1