Oracle Application Express 4 Recipes

Chapter 3. Wiring up Application Logic

If you are an ASP.NET developer, you're probably familiar with the codebehind model introduced by Microsoft to separate the presentation from the logic layer. In a codebehind page, execution of code is event-based. You specify blocks of code to execute when a page loads or when a button is clicked.

The APEX logic layer works in a similar fashion. Perhaps the best way to summarize how it works is this: Page execution is segmented into different chronological events—points at which application logic can be inserted. For instance, the back end execution of a typical APEX page is segmented into two major events, Page Rendering and Page Processing, both of which consist of smaller events that can trigger application ...