Calling a Stored Procedure with a Command

You can also use a command when calling a stored procedure. The following code calls a stored procedure in the Northwind sample database, called CustOrdersOrders, which is defined as follows:

CREATE PROCEDURE CustOrdersOrders @CustomerID nchar(5) AS
SELECT OrderID, OrderDate, RequiredDate, ShippedDate
FROM Orders
WHERE CustomerID = @CustomerID
ORDER BY OrderID

This stored procedure is similar to the command used in Command Object Parameters, in that it takes a customer ID parameter and returns information about that customer's orders. The code below uses this stored procedure as the source for an ADO Recordset.

Using the stored procedure allows you to access another capability of ADO: the Parameters collection Refresh method. By using this method, ADO can automatically fill in all information about the parameters required by the command at run time. There is a performance penalty in using this technique, because ADO must query the data source for the information about the parameters.

Other important differences exist between the code below and the code in Command Object Parameters, where the parameters were entered manually. First, this code does not set the Prepared property to True because it is a SQL Server stored procedure and is precompiled by definition. Second, the CommandType property of the Command object changed to adCmdStoredProc in the second example to inform ADO that the command was a stored procedure.

Finally, in the second example the parameter must be referred to by index when setting the value, because you might not know the name of the parameter at design time. If you do know the name of the parameter, you can set the new NamedParameters property of the Command object to True and refer to the property's name. You might wonder why the position of the first parameter mentioned in the stored procedure (@CustomerID) is 1 instead of 0 (objCmd(1) = "ALFKI"). This is because parameter 0 contains a return value from the SQL Server stored procedure.

'BeginAutoParamCmd
' Set CommandText equal to the stored procedure name.
objCmd.CommandText = "CustOrdersOrders"
objCmd.CommandType = adCmdStoredProc
        
' Connect to the data source.
Set objConn = GetNewConnection
objCmd.ActiveConnection = objConn
    
' Automatically fill in parameter info from stored procedure.
objCmd.Parameters.Refresh

' Set the param value.
objCmd(1) = "ALFKI"

' Execute once and display...
Set objRs = objCmd.Execute
    
Debug.Print objParm1.Value
Do While Not objRs.EOF
    Debug.Print vbTab & objRs(0) & vbTab & objRs(1) & vbTab & _
                objRs(2) & vbTab & objRs(3)
    objRs.MoveNext
Loop
    
' ...then set new param value, re-execute command, and display.
objCmd(1) = "CACTU"
Set objRs = objCmd.Execute
    
Debug.Print objParm1.Value
Do While Not objRs.EOF
    Debug.Print vbTab & objRs(0) & vbTab & objRs(1) & vbTab & _
                objRs(2) & vbTab & objRs(3)
    objRs.MoveNext
Loop
    
objRs.Close
objConn.Close
'EndAutoParamCmd