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Avoiding Bugs
The best way to deal with bugs is to avoid them in the first place. Proper coding techniques can really aid you in this process. Using the Option Explicit statement, strong-typing, naming standards, and tight scoping can help you eliminate bugs in your code.
Option Explicit
Option Explicit requires that you declare all your variables before you use them. Including Option Explicit in each Form, Code, and Report module helps the VBA compiler find typos in the names of variables.Chapter 7, "VBA: An Introduction," the Option Explicit statement is a command that you can manually insert into the General Declarations section of any Code, Form, or Report module. If you prefer, you can have Access automatically insert the Option Explicit statement. To accomplish this, select Require Variable Declaration from the Editor tab after choosing Tools, Options from within the Visual Basic Editor. After you select that setting, Access inserts an Option Explicit statement in the General Declarations section of all new modules. This setting does not affect existing modules.
Strong-Typing
Chapter 7 covers the process of strong-typing your variables. Strong-typing a variable means indicating at declaration time the type of data you will store in a variable. For example, Dim intCounter As Integer initializes a variable that contains integers. If elsewhere in your code you assign a character string to intCounter, the compiler will catch the error.
Naming Standards
Naming standards can also go a long way toward helping you eliminate errors. The careful naming of variables makes your code easier to read and makes the intended use of the variable more obvious. Problem code tends to stand out when you have judiciously followed naming conventions. Chapter 1, "Access as a Development Tool," covers naming standards. Appendix B, "Naming Conventions," covers the details of naming standards.
Variable Scoping
Finally, giving your variables the narrowest scope possible reduces the chances of one piece of code accidentally overwriting a variable within another piece of code. You should use local variables whenever possible. Use module-level and global variables only when it is necessary to see the value of a variable from multiple subroutines or multiple modules. For more information about the issues surrounding variable scoping, see Chapter 7.
Bugs Happen!
Unfortunately, no matter what you do to prevent problems and errors, they still creep into your code. Probably the most insidious type of error is a logic error. A logic error is sneaky because it escapes the compiler; your code compiles, but simply does not execute as planned. This type of error might become apparent when you receive a runtime error or when you don't get the results you expected. This is where the debugger comes to the rescue.
