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…
Minimizing stateful code
First we need to define what a state is. A state means that the object has variable(s) that may cause it to behave differently, depending on the content of the variables. As an example, the Forms collection is stateful: Forms(“SomeForm”).Visible = False This is legal code and will compile but we can’t be assured that…
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 Not all controls have a ControlSource property and thus can fail to run. A…
Microsoft Access File Extensions
Microsoft Access saves information under the following file formats: File Format Extension Access Project (2007, 2010) .adp Access Blank Project Template (2007, 2010) .adn Access Database (2007, 2010, 2013, 2016) .accdb Access Record-Locking Information (2007, 2010, 2013, 2016) laccdb Access Web App Reference .accdw Access Signed Packages .accdc Access Database, used for Add-ins .accda Access…
Access DateValue() function to SQL Server equivalent
What is the SQL Server equivalent to Access DateValue() function? Access SQL DateValue([Event Timestamp]) SQL Server Equivalent cast([Event Timestamp] as date) convert(date, [Event Timestamp])
“Truthy” and “Falsy” Values
VBA is quite very loose in what it deems “truthy” and “falsy”. For example, this procedure can produce surprising result: If Me.MyBitField.Value = True Then ‘It is true Else ‘It is false End If At the first glance, it seems expected that if the bit field is set to 1, it would succeed. But in…
Creating a Make Table Query
Before we create the Make Table Query, you might like to create a new blank database file. This is so we have a separate database into which we can paste the new table from the query. In this exercise I have called it HistoricData.accdb. Here is the procedure to create a Make Table Query: Open…
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.
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…