Parameter.Direction property (DAO)

Applies to: Access 2013, Office 2013

Syntax

expression .Direction

expression A variable that represents a Parameter object.

Remarks

The setting or return value is a Long that can be set to one of the ParameterDirectionEnum constants.

Use the Direction property to determine whether the parameter is an input parameter, output parameter, both, or the return value from the procedure. Some ODBC drivers do not provide information on the direction of parameters to a SELECT statement or procedure call. In these cases, it is necessary to set the direction prior to executing the query.

For example, the following procedure returns a value from a stored procedure named "get_employees":

{? = call get_employees}

This call produces one parameter — the return value. You need to set the direction of this parameter to dbParamOutput or dbParamReturnValue before executing the QueryDef.

You need to set all parameter directions except dbParamInput before accessing or setting the values of the parameters and before executing the QueryDef.

You should use dbParamReturnValue for return values, but in cases where that option is not supported by the driver or the server, you can use dbParamOutput instead.

The Microsoft SQL Server driver automatically sets the Direction property for all procedure parameters. Not all ODBC drivers can determine the direction of a query parameter. In these cases, it is necessary to set the direction prior to executing the query.

Example

This example uses the Direction property to configure the parameters of a query to an ODBC data source.

Sub DirectionX() 
 
 Dim wrkMain As Workspace 
 Dim conMain As Connection 
 Dim qdfTemp As QueryDef 
 Dim rstTemp As Recordset 
 Dim strSQL As String 
 Dim intLoop As Integer 
 
 ' Create ODBC workspace and open a connection to a 
 ' Microsoft SQL Server database. 
 Set wrkMain = CreateWorkspace("ODBCWorkspace", _ 
 "admin", "", dbUseODBC) 
 
 ' Note: The DSN referenced below must be configured to 
 ' use Microsoft Windows NT Authentication Mode to 
 ' authorize user access to the Microsoft SQL Server. 
 Set conMain = wrkMain.OpenConnection("Publishers", _ 
 dbDriverNoPrompt, False, _ 
 "ODBC;DATABASE=pubs;DSN=Publishers") 
 
 ' Set SQL string to call the stored procedure 
 ' getempsperjob. 
 strSQL = "{ call getempsperjob (?, ?) }" 
 
 Set qdfTemp = conMain.CreateQueryDef("", strSQL) 
 
 With qdfTemp 
 ' Indicate that the two query parameters will only 
 ' pass information to the stored procedure. 
 .Parameters(0).Direction = dbParamInput 
 .Parameters(1).Direction = dbParamInput 
 
 ' Assign initial parameter values. 
 .Parameters(0) = "0877" 
 .Parameters(1) = 0 
 
 Set rstTemp = .OpenRecordset() 
 
 With rstTemp 
 ' Loop through all valid values for the second 
 ' parameter. For each value, requery the recordset 
 ' to obtain the correct results and then print out 
 ' the contents of the recordset. 
 For intLoop = 1 To 14 
 qdfTemp.Parameters(1) = intLoop 
 .Requery 
 Debug.Print "Publisher = " & _ 
 qdfTemp.Parameters(0) & _ 
 ", job = " & intLoop 
 Do While Not .EOF 
 Debug.Print , .Fields(0), .Fields(1) 
 .MoveNext 
 Loop 
 Next intLoop 
 .Close 
 End With 
 
 End With 
 
 conMain.Close 
 wrkMain.Close 
 
End Sub