sql - 如何将空值发送到存储过程？

Question

我的存储过程如下所示:

CREATE PROCEDURE [dbo].[insertCompList_Employee]
   @Course_ID int, 
   @Employee_ID int, 
   @Project_ID int = NULL, 
   @LastUpdateDate datetime = NULL,  
   @LastUpdateBy int = NULL                     
AS 
BEGIN 
   SET NOCOUNT ON 

   INSERT INTO db_Competency_List(Course_ID, Employee_ID, Project_ID, LastUpdateDate, LastUpdateBy) 
   VALUES (@Course_ID, @Employee_ID, @Project_ID, @LastUpdateDate, @LastUpdateBy) 
END 

我的asp.net vb代码后面如下:

    dc2.insertCompList_Employee(
    rdl_CompList_Course.SelectedValue, 
    RadListBox_CompList_Select.Items(i).Value.ToString, 
    "0",
    DateTime.Now, 
    HttpContext.Current.Session("UserID")
)

我想插入一个 null Project_ID 的值而不是 0
我试过 NULL , 'NULL'但它返回错误。

Answer 1

使用内置值:DBNull.Value
http://msdn.microsoft.com/en-us/library/system.dbnull.value.aspx?cs-save-lang=1&cs-lang=vb#code-snippet-1