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Parameter object (DAO)

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Applies to: Access 2013, Office 2013

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.

    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