Designing Active Server Pages

Chapter 3. Exception Handling

Errors happen. Regardless of how skilled a given programmer might be, there is no way he can create truly bug-free code. Programming errors can be broken down into two broad categories: logical errors and implementation errors. Before starting to actually write code, a developer must have a solid understanding of what application she is creating, and the logic behind this application.

For example, when creating an e-commerce web application, a developer might decide that once a user decides to purchase an item, he is taken directly to a page to enter his billing and shipping information. Many users today are used to a shopping cart system, in which they can purchase multiple items online and then proceed to a “check out” page, where they can review a summary of the goods being purchased and enter the needed billing and shipping information. By not providing a shopping cart system, your users may find your site confusing and burdensome to use. Logical errors are often high-level errors, costing immense time and money to fix, since they are usually not caught until late in the product development cycle.

Implementation errors are those errors residing in the actual code. In an e-commerce site, if not all of the items selected by the user appear in the summary listing on the “check out” page, an implementation error has occurred. To summarize: flaws existing within the high-level view of the application are logical errors; errors or bugs resulting from ...