Microsoft Access Linked TablesSignificantly Improve the Performance of Microsoft Access Databases with Linked Tables

Provided by: Luke Chung, FMS President

Automate Microsoft Access Application Deployments

A split database architecture is best for developing, maintaining, and deploying Microsoft Access applications. The front-end database contains all the Access objects except the tables which reside in a separate back-end Access Jet database. The front-end database links to the tables in the back-end database, so it can be updated without worrying about changes to the data.

This is particularly important for multi-user applications where each user has a copy of the front-end database on their machine sharing the same centralized data. When the application is enhanced (new queries, forms, reports, code, etc.), it is simply distributed to each user. Programs like our Total Access Startup can centralize and automate the distribution process.

If you are not familiar with a split database architecture, read our paper on Splitting Microsoft Access Databases to Improve Performance and Simplify Maintainability

When a single database is converted to a split-database design, one sometimes sees significant performance degradation, especially over a network. Speed may vary with different portions of the application and number of users. Some people settle for this but there may be a simple way to significantly improve performance.

When a database is opened, Microsoft Access creates a lock file on disk. You may see these are *.LDB or *.LACCDB files. When the database is closed, the lock file is deleted.

This is not a big deal for a single MS Access database application which would create the lock file when the database is opened and maintain it until the database is closed. But in a linked database design, the lock file on the back-end database may be created and deleted every time a table is opened and closed. When no connections to any tables on the back end database remain open, the lock file is deleted. That takes time.

You can significantly improve the performance of your Access database by maintaining an open connection to the back-end database throughout the time your front-end database is opened.

By forcing Access to keep the linked table's database open, Access avoids creating a new lock on the backend database every time one of its tables is used. This lets you open tables, forms, and reports much faster. Over a network, you'll usually see a substantial improvement with how quickly a form opens when it's based on a linked table.

To create a persistent connection to the linked database, open a MS Access database variable in VBA using the DAO OpenDatabase method. Keep this variable open as long as your application is running.

Procedure Code

The procedure below supports multiple backend databases. Edit the section with the list of databases to match your backend database(s):

Sub OpenAllDatabases(pfInit As Boolean)
  ' Open a handle to all databases and keep it open during the entire time the application runs.
  ' Params  : pfInit   TRUE to initialize (call when application starts)
  '                    FALSE to close (call when application ends)
  ' Source  : Total Visual SourceBook

  Dim x As Integer
  Dim strName As String
  Dim strMsg As String
  ' Maximum number of back end databases to link
  Const cintMaxDatabases As Integer = 2

  ' List of databases kept in a static array so we can close them later
  Static dbsOpen() As DAO.Database
  If pfInit Then
    ReDim dbsOpen(1 To cintMaxDatabases)
    For x = 1 To cintMaxDatabases
      ' Specify your back end databases
      Select Case x
        Case 1:
          strName = "H:\folder\Backend1.mdb"
        Case 2:
          strName = "H:\folder\Backend2.mdb"
      End Select
      strMsg = ""

      On Error Resume Next
      Set dbsOpen(x) = OpenDatabase(strName)
      If Err.Number > 0 Then
        strMsg = "Trouble opening database: " & strName & vbCrLf & _
                 "Make sure the drive is available." & vbCrLf & _
                 "Error: " & Err.Description & " (" & Err.Number & ")"
      End If

      On Error GoTo 0
      If strMsg <> "" Then
        MsgBox strMsg
        Exit For
      End If
    Next x
    On Error Resume Next
    For x = 1 To cintMaxDatabases
    Next x
  End If
End Sub

Call this when your application starts:

OpenAllDatabases True

When you finish, call this to close the database variables/handles:

OpenAllDatabases False

For instance, if you have a form that controls the application and remains open during the entire time the user is using your database, add the code to the OnOpen and OnClose events.

This simple technique yields considerable performance gains.

Find Performance Tips for Microsoft AccessAdditional Resources

Good luck!

Table Design

Query Design

Form Design

Form Tips and Mistakes

Copy Command Button and Keep Picture

Module VBA to Forms and Controls

Form Navigation Caption

Resync Record in a Subform

Synchronize Two Subforms

Multiple OpenArgs Values

Late Bind Tab Subforms

Subform Reference to Control Rather than Field

Tab Page Reference

Shortcut Keys

Combo Box Top 6 Tips

Properties and Validation

Select First Item

Cascading Combo Boxes

Zip, City, State AutoFill

Report Design

Suppress Page Headers and Footers on the First Page of Your Report

Add the NoData Event

Annual Monthly Crosstab Columns

Design Environment

Add Buttons to the Quick Access Toolbar

Collapse the Office Ribbon for more space

VBA Programming

Basics: Forms and Controls

Run VBA Code from a Macro

Use Nz() to Handle Nulls

Avoid Exits in the Body of a Procedure

Shortcut Debugging Keys

Set Module Options

Math Rounding Issues

Rename a File or Folder

Avoid DoEvents in Loops

Age Calculations

Weekday Math

Send Emails with DoCmd.SendObject

Source Code Library

Microsoft Access Modules Library

Microsoft Access Modules

VBA Error Handling

Error Handling and Debugging Techniques

Error Number and Description Reference

Basic Error Handling

Pinpointing the Error Line

Performance Tips

Linked Database

Subdatasheet Name

Visual SourceSafe


Runtime Downloads

Simulate Runtime

Prevent Close Box

Disable Design Changes

Broken References

Remote Desktop Connection Setup

Terminal Services and RemoteApp Deployment

Reboot Remote Desktop

Missing Package & Deployment Wizard

Avoid Program Files Folder

Unavailable Mapped Drives

Microsoft Access Front-End Deployment

System Admin

Disaster Recovery Plan

Compact Database

Compact on Close

Database Corruption

Remove 'Save to SharePoint Site' Prompt from an Access Database

Class Not Registered Run-time Error -2147221164

Inconsistent Compile Error

Decompile Database

Bad DLL Calling Convention

Error 3045: Could Not Use

Converting ACCDB to MDB

SQL Server Upsizing

Microsoft Access to SQL Server Upsizing Center

Microsoft Access to SQL Server Upsizing Center

When and How to Upsize Access to SQL Server

SQL Server Express Versions and Downloads

Cloud and Azure

Cloud Implications

MS Access and SQL Azure

Deploying MS Access Linked to SQL Azure

SQL Server Azure Usage and DTU Limits

Visual Studio LightSwitch

LightSwitch Introduction

Comparison Matrix

Additional Resources

Connect with Us


Free Product Catalog from FMS