ACC2000: To Help Prevent Database Bloat, Explicitly Close Recordsets

In Microsoft Access, if you use Data Access Objects (DAO) to open a recordset and you do not explicitly close the recordset, DAO may hold onto the memory that it used for its previous compile until the next recordset is opened.

Because the recordset memory is not released, each time that you loop through code, DAO may recompile, using more memory and increasing the size of the database.

To avoid consuming unnecessary resources and increasing database size, use the Close method of the Recordset object to explicitly close the recordset's memory when you no longer require the recordset.

If the database has increased in size because you did not use the Close method of the Recordset object, you can reduce the size of the database by compacting it.

Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements. When you create a Recordset (or QueryDef) object in code, explicitly close the object when you are finished with it. Microsoft Access automatically closes Recordset and QueryDef objects under most circumstances; however, if you explicitly close the object in your code, you can avoid occasional instances when the object remains open. The following steps show you how to use DAO to close the Recordset and QueryDef objects.

1. Start Microsoft Access.
2. Open the sample database Northwind.mdb.NOTE: The sample code in this article uses Microsoft Data Access Objects. For this code to run properly, you must reference the Microsoft DAO 3.6 Object Library. To do so, click References on the Tools menu in the Visual Basic Editor, and make sure that the Microsoft DAO 3.6 Object Library check box is selected.
   
   
3. Copy the following code to a new module. The following sample code opens and closes a Recordset and a QueryDef object and displays both Recordset and QueryDef information in message boxes.

   Sub CloseObjects()
      Dim db As Database
      Dim rs As Recordset
      Dim qd As QueryDef
   
      Set db = CurrentDb
      Set rs = db.OpenRecordset("Employees", dbOpenTable)
      Set qd = db.QueryDefs("Invoices")
   
      rs.MoveLast ' Move to the last record in the Recordset.
   
      MsgBox "The Employees Recordset is open." & vbcr & _
         "The last Employee ID is " & rs![EmployeeID] & "."
   
      Msgbox "The Invoices query definition is open." & vbcr & _
         "The first field in the query is " & qd.Fields(0).Name
   
      ' Explicitly close the Recordset and QueryDef objects.
      rs.Close
      qd.Close
   End Sub
   
   					

4. Run the CloseObjects subroutine.