You can use a command to call a stored procedure. The code sample at the end of this topic refers to 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
See your SQL Server documentation for more information about how to define and call stored procedures.
This stored procedure is similar to the command used in Command Object Parameters. It takes a customer ID parameter and returns information about that customer's orders. The following code sample 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 following code sample 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 On Error GoTo ErrHandler: Dim objConn As New ADODB.Connection Dim objCmd As New ADODB.Command Dim objParm1 As New ADODB.Parameter Dim objRs As New ADODB.Recordset ' 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 'clean up objRs.Close objConn.Close Set objRs = Nothing Set objConn = Nothing Set objCmd = Nothing Set objParm1 = Nothing Exit Sub ErrHandler: 'clean up If objRs.State = adStateOpen Then objRs.Close End If If objConn.State = adStateOpen Then objConn.Close End If Set objRs = Nothing Set objConn = Nothing Set objCmd = Nothing Set objParm1 = Nothing If Err <> 0 Then MsgBox Err.Source & "-->" & Err.Description, , "Error" End If 'EndAutoParamCmd 'BeginNewConnection Private Function GetNewConnection() As ADODB.Connection Dim oCn As New ADODB.Connection Dim sCnStr As String sCnStr = "Provider='SQLOLEDB';Data Source='MySqlServer';" & _ "Integrated Security='SSPI';Initial Catalog='Northwind';" oCn.Open sCnStr If oCn.State = adStateOpen Then Set GetNewConnection = oCn End If End Function 'EndNewConnection