Microsoft Access Blog

Use TryGet pattern for transient values

A number of objects may have extra properties or something where it might not exist for all instances. A good example might be finding Controlsource property on an Access.Control variable:

For Each ctl In Me.Controls
  Debug.Print ctl.ControlSource 'A potential error
Next

For Each ctl In Me.Controls

Debug.Print ctl.ControlSource 'A potential error

Not all controls have a ControlSource property and thus can fail to run. A common approach is to use OERN:

For Each ctl In Me.Controls
  On Error Resume Next
  Debug.Print ctl.ControlSource 'A potential error
  On Error GoTo 0
Next

For Each ctl In Me.Controls

On Error Resume Next

Debug.Print ctl.ControlSource 'A potential error

On Error GoTo 0

This will work…

Designing a lookup table with logic

It is very common for us to embed some kind of logic based on a lookup table or in some cases, a column of a table. Because we have application logic connected to it, the code are fragile and subject to changes as the requirements develops. We want to avoid this situation where we might…

Normalize all constraints’ & indices’ names

Constraints that are created by SSMA or by user via SSMS tend to have ugly names. Worse, auto-generated names are not stable across backups. Meaning if you restore a new database based on a copy of another database, the constraint names will change. That create huge problems during migrations because scripts that references constraint will…

Prefer compile time errors over run time errors

In VBA, there are several features that allow us to do things that may not be checked at the compile time. In particular, it is possible to write several late-bound expressions which means that it can potentially contain run-time errors. One common misconception about late-binding is that it’s a matter of adding a reference and…

Why does Excel have a problem when using code in Access?

When you use code to refer to Excel (and other programs as well) you need to be careful not to use any code that does not refer back to the instantiated application object. If you do so then you will find that Access instantiates another Excel (or other program) object which is not visible to…

Use controls, not fields

Sometimes we need to use fields from a RecordSource that aren’t shown on the form. It is legal to reference them directly even if they don’t have a control. For example, we can have a form bound to a RecordSource like so:

SELECT
  c.CompanyID,
  c.CompanyName
FROM Companies;

SELECT

c.CompanyID,

c.CompanyName

FROM Companies;

And only display CompanyName in a textbox but not show the CompanyID….

Module level variables

It is common to create a big wall of declaration in a module such as this:

Private strCompanyName As String
Private dteOrderDate As Date
Private lngOrderID As Long
Private objEmail As Object
Private objOutlook As Object

Private strCompanyName As String

Private dteOrderDate As Date

Private lngOrderID As Long

Private objEmail As Object

Private objOutlook As Object

While the code will compile and work fine, the discoverability and naming of the module level variables does become difficult and unwieldy. To help cut down on this ambiguity, it is recommended to create a private user-defined type…

Access CDate() function to SQL Server equivalent

What is the SQL Server equivalent to Access CDate() function? Access SQL CDate([Event Timestamp]) SQL Server Equivalent cast([Event Timestamp] as datetime) convert(datetime, [Event Timestamp])

Microsoft Access 2003 Language Reference [Access 2003 VBA Language Reference]

This reference contains conceptual overviews, programming tasks, samples, and references to guide you in developing solutions based on Microsoft Access. The reference contains the following sections: What’s New: Provides a list of new members by object and in alphabetical order. Concepts: Provides important concepts for developing custom Access solutions. Reference: Provides reference materials for the Access…

Access NZ() function to SQL Server equivalent

What is the SQL Server equivalent to Access NZ() function? Access SQL NZ([Event Timestamp]) SQL Server Equivalent COALESCE([Event Timestamp],0) ISNULL([Event Timestamp],0) * do not confuse this with the Access isnull() function.