There are cases where a table’s primary key is referred to often in the code. In fact, it might have some special meanings in code. It is highly encouraged to avoid the use of IDENTITY or AutoNumber (or any auto-incrementing schema) for those keys because it is also usually desirable to create a VBA Enum…
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…
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.
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…
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:
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For Each ctl In Me.Controls Debug.Print ctl.ControlSource 'A potential error Next |
Not all controls have a ControlSource property and thus can fail to run. A common approach is to use OERN:
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For Each ctl In Me.Controls On Error Resume Next Debug.Print ctl.ControlSource 'A potential error On Error GoTo 0 Next |
This will work…
Hiding the Navigation Pane with VBA
Once you have created an Access Database Application to be used by other people, it may well be important for you to prevent users from gaining access to any of its design features. By this I mean, you may not want users to modify your tables, forms and queries etc in design view (inadvertently or…
Self-documenting code
Strong preference should be given to writing code that is self-documenting. A common approach is to write a lot of comments, but the problem with comments are twofold: It actually can harm the readability because it adds to the overall length of code to read and understand. It must be correct or it can end…
Module level variables
It is common to create a big wall of declaration in a module such as this:
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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 IIf() function to SQL Server equivalent
What is the SQL Server equivalent to Access IIf() function? Access SQL IIf([ResultValue]>=1, [Result Value], Null) SQL Server CASE WHEN [Result Value]>=1 THEN [Result Value] ELSE NULL END
Use properties instead of constant or magic numbers
A common programming mistake is to hard-code literals that corresponds to some property. That is particularly true with certain controls like tab controls & pages. The tab control exposes a Value property that indicates the current tab and the pages contains a PageIndex property that indicates its position in the tabs of the control. Thus,…