Datasheet

Chapter 1

Employ a Change Plan

As well as information hiding, there are other techniques that can assist in reducing the impact

of change, and these should be prescribed in a change plan. For example, the change plan might

specify that:

❑ Named constants should be used wherever possible in place of hard-coded values.

❑ If the application is to be multi-lingual, then care must be taken to identify and

separate out all the text to be used so that it can be easily localized (translated). This

may mean allowing additional screen space to accommodate certain languages or

considering the use of pictorial icons in place of text.

❑ Settings and configuration options should be stored in the Registry rather than hard-

coded within the application itself.

❑ Generic and widely used processes should be identified and grouped together in

modules, separate from code with specialized functionality only called by specific

parts of an application.

One of the best ways to determine which elements to incorporate into a change plan is to

perform post-implementation reviews just after a project has been delivered (or post-mortems if

they don't get that far!). Identify what changed during the project lifecycle, what impact that

change had, and how the impact of that change could have been lessened. Then put that

knowledge into your next change plan and make sure you don't make the same mistake twice!

Coding

Once your design is complete, you can start to code. That's the part of the process that we will

be examining in most detail throughout the rest of this book. We will start by looking at the

specifics of the VBA language and the structure of VBA procedures and modules. Then we will

look at the Access object model and how this can be manipulated in code. After a short look at

some more advanced programming techniques, we will look at how to handle errors that might

occur in our application, how to make the best use of class modules, libraries and add-ins, and

how to optimize the performance of our application. We will also look at some of the issues we

need to be aware of if our application is being used in a multi-user environment and how we

can bring some of the power of the Internet to our Access application. Finally, we will look at

the finishing touches we can apply to round out our application and give it a more professional

look and feel.

Testing

There are a number of quality assurance practices that you can apply to your project, but by far

the most basic is testing. This involves unit testing (or component testing) where the developer

verifies that the code he or she has written works correctly; system testing where someone

checks that the entire application works together as expected; and acceptance testing, where the

users of the application check that the results the application produces are those they desire (or,

at least, that they are those they asked for in the first place!).