Question: I'm trying to execute a stored procedure (against SQL Server 2005 through the ODBC driver) and I recieve the following error:

> 
> Procedure or Function 'GetNodeID' expects parameter '@ID', which was not supplied.
> 
> 
> 

@ID is the OUTPUT parameter for my procedure, there is an input @machine which is specified and is set to null in the stored procedure:

```
ALTER PROCEDURE [dbo].[GetNodeID] 
@machine nvarchar(32) = null,
@ID int OUTPUT
AS
BEGIN
SET NOCOUNT ON;

IF EXISTS(SELECT * FROM Nodes WHERE NodeName=@machine)
BEGIN
    SELECT @ID = (SELECT NodeID FROM Nodes WHERE NodeName=@machine)
END
ELSE
BEGIN
    INSERT INTO Nodes (NodeName) VALUES (@machine)
    SELECT @ID = (SELECT NodeID FROM Nodes WHERE NodeName=@machine)
END
END

```

The following is the code I'm using to set the parameters and call the procedure:

```
        OdbcCommand Cmd = new OdbcCommand("GetNodeID", _Connection);
        Cmd.CommandType = CommandType.StoredProcedure;

        Cmd.Parameters.Add("@machine", OdbcType.NVarChar);
        Cmd.Parameters["@machine"].Value = Environment.MachineName.ToLower();

        Cmd.Parameters.Add("@ID", OdbcType.Int);
        Cmd.Parameters["@ID"].Direction = ParameterDirection.Output;

        Cmd.ExecuteNonQuery();
        _NodeID = (int)Cmd.Parameters["@Count"].Value;

```

I've also tried using Cmd.ExecuteScalar with no success. If I break before I execute the command, I can see that @machine has a value.

If I execute the procedure directly from Management Studio, it works correctly.

Any thoughts? Thanks

Answer: 
Try replacing :

```
OdbcCommand Cmd = new OdbcCommand("GetNodeID", _Connection);
Cmd.CommandType = CommandType.StoredProcedure;

```

With :

```
OdbcCommand Cmd = new OdbcCommand("{call GetNodeID(?,?)}", _Connection);

```

More info :

<http://support.microsoft.com/kb/310130>
I'm not exactly sure what you mean by

> 
> there is an input @machine which is
>  specified and is set to null in the
>  stored procedure
> 
> 
> 

In your proc's signature, this line:

```
@machine nvarchar(32) = null

```

doesn't mean that you're setting `@machine` to null inside the proc - it means you're assigning a default value to be used in case the parameter is missing (in this case, `null` is the value to be used for a missing param).

Getting the error about `@ID` being missing would happen if you were calling this stored procedure without passing any parameters at all (`@machine` would not be flagged as a problem since it has a default value defined). Your code example looks fine to me - are you sure the stored proc isn't being called from somewhere else in your program (somewhere where no parameters are being added)?