Share via

Parameter Object

  • Article
Access Developer Reference

A Parameter object represents a value supplied to a query. The parameter is associated with a QueryDef object created from a parameter query.

Remarks

Parameter objects allow you to change the arguments in a frequently run QueryDef object without having to recompile the query.

Using the properties of a Parameter object, you can set a query parameter that can be changed before the query is run. You can:

  • Use the Name property to return the name of a parameter.
  • Use the Value property to set or return the parameter values to be used in the query.
  • Use the Type property to return the data type of the Parameter object.
  • Use the Direction property to set or return whether the parameter is an input parameter, an output parameter, or both.

Example

This example demonstrates Parameter objects and the Parameters collection by creating a temporary QueryDef and retrieving data based on changes made to the QueryDef object's Parameters. The ParametersChange procedure is required for this procedure to run.

Visual Basic for Applications 
  Sub ParameterX()

Dim dbsNorthwind As Database
Dim qdfReport As QueryDef
Dim prmBegin As Parameter
Dim prmEnd As Parameter


Set dbsNorthwind = OpenDatabase("Northwind.mdb")


' Create temporary QueryDef object with two
' parameters.
Set qdfReport = dbsNorthwind.CreateQueryDef("", _
"PARAMETERS dteBegin DateTime, dteEnd DateTime; " & _
"SELECT EmployeeID, COUNT(OrderID) AS NumOrders " & _
"FROM Orders WHERE ShippedDate BETWEEN " & _
"[dteBegin] AND [dteEnd] GROUP BY EmployeeID " & _
"ORDER BY EmployeeID")
Set prmBegin = qdfReport.Parameters!dteBegin
Set prmEnd = qdfReport.Parameters!dteEnd


' Print report using specified parameter values.
ParametersChange qdfReport, prmBegin, #1/1/95#, _
prmEnd, #6/30/95#
ParametersChange qdfReport, prmBegin, #7/1/95#, _
prmEnd, #12/31/95#


dbsNorthwind.Close


End Sub


Sub ParametersChange(qdfTemp As QueryDef, _
prmFirst As Parameter, dteFirst As Date, _
prmLast As Parameter, dteLast As Date)
' Report function for ParameterX.


Dim rstTemp As Recordset
Dim fldLoop As Field


' Set parameter values and open recordset from
' temporary QueryDef object.
prmFirst = dteFirst
prmLast = dteLast
Set rstTemp = _
qdfTemp.OpenRecordset(dbOpenForwardOnly)
Debug.Print "Period " & dteFirst & " to " & dteLast


' Enumerate recordset.
Do While Not rstTemp.EOF


  ' Enumerate Fields collection of recordset.
  For Each fldLoop In rstTemp.Fields
     Debug.Print " - " & fldLoop.Name & " = " & fldLoop;
  Next fldLoop

  Debug.Print
  rstTemp.MoveNext



Loop


rstTemp.Close


End Sub