This chapter revolved around a small database application that still managed to require a variety of SQL and PHP and ASP programming features. One lesson that you could learn from this is that when you are developing an application, it is possible to test your logic and design on a small system. You need not and should not enter in all your data before you have tested the basics. Your test system needs to have some variety of data, but it does not need large numbers of records.
As in the last chapter, special characters—for example, the single quotation mark—required special handling. This was discovered just because the test data originally used contained an apostrophe. This means you need to include special characters in your testing.
You probably ran into pesky syntax bugs involving single and double quotation marks, opening and closing parentheses, curly brackets and tags. Techniques to employ for debugging include:
Use of print and Response.Write to output query statements and any other variable that might be questionable.
Dividing steps into multiple steps (such as construction of a string for a complex query). Error codes from PHP and ASP are given in terms of line numbers.
Examination of the HTML source.
This chapter also exposed some differences in the SQL for MySQL versus the SQL for Access. If you do go from one system to another and find that something fails to work, your best bet is to go online to find an answer.
The logic for the ASP and PHP systems is the same. Moreover, the logic of one task carries over to another task. Try to see the similarity between tasks so you can copy sections of code from script to script and build on your experience for new applications.