VBScript: Passing a parameter with a null value to a stored procedure?

Question

In VBScript (ASP environment), is it possible to pass a parameter with a null value to a stored procedure?

Answer 1

Passing null to a stored procedure, using a command object.

Set cn = CreateObject("ADODB.Connection")
Set cmd = CreateObject("ADODB.Command")
cn.Open "Provider=SQLOLEDB.1;Integrated Security=SSPI;Data Source=.\Test"
Set cmd.ActiveConnection = cn
cmd.CommandText = "TestTable.sp_ModifyData"
cmd.CommandType = 4
cmd.NamedParameters = True

set cnParam = cmd.CreateParameter("@RowID",3,3,,-1)
cmd.Parameters.Append cnParam
set cnParam = cmd.CreateParameter("@AddRemoveModify",3,1,,0)
cmd.Parameters.Append cnParam
set cnParam = cmd.CreateParameter("@Value1",3,1,,0)
cmd.Parameters.Append cnParam
set cnParam = cmd.CreateParameter("@Value2",8,1,-1,"Test")
cmd.Parameters.Append cnParam
set cnParam = cmd.CreateParameter("@value3",5,1,,null)
cmd.Parameters.Append cnParam
set cnParam = cmd.CreateParameter("@value4",5,1,,0)
cmd.Parameters.Append cnParam
set cnParam = cmd.CreateParameter("@value5",8,1,-1,"")
cmd.Parameters.Append cnParam
cmd.Execute
cn.Close
Set cmd = Nothing
Set cn = Nothing

Sorry I didn't put much thought into naming the fields in my database.

Answer 2

Try vbNullString or vbNullChar. You may also need adParamNullable.

set cnParam = cmd.CreateParameter("@value3",5,1,,vbNullString)  
cnParam.Attributes = adParamNullable  
cmd.Parameters.Append cnParam

Update:

Actually this worked for me:

set cnParam = cmd.CreateParameter("@value3",5,1,,Null)  
cnParam.Attributes = adParamNullable  
cmd.Parameters.Append cnParam

Huh, this worked too:

set cnParam = cmd.CreateParameter("@value3",5,1,,Null)  
cmd.Parameters.Append cnParam

Go figure.

Answer 3

If you're building strings, and checking/guarding against SQL Injection, you can simply use the word null in your SQL string, or comma delimited EXEC statement.

'calling a stored proc.
strSQL = "EXEC UpdateCustomer @CustomerID=" & iCustomerID + ",@PhoneNumber=null"

Here's how to use null in a manually built string to send to the DB

strSQL = "UPDATE Customer SET PhoneNumber = null WHERE CustomerID = " + iCustomerID

Answer 4

Short answer: Set the parameter value to Null (VBScript keyword).