Developing Large Web Applications

Chapter 6. Data Management

As you examine the design for a web page, it’s important to distinguish between data on the page that is dynamic and data that is static. Dynamic data, such as a list of search results, changes each time the page is loaded (based on the query); static data, such as a label for the query box, does not. The distinction between static and dynamic data is important because each requires its own management strategy. On the one hand, static data is easy—you simply specify it directly within the HTML of the page. With dynamic data, however, you must enlist the help of a server-side scripting language, such as PHP, so that you can interact with backend systems to store and retrieve the data. In this chapter, we look at techniques for managing dynamic data.

One of the most important goals for managing dynamic data in a large web application is to establish a clearly defined data interface through which to interact with the backend. A clearly defined data interface allows modules in the user interface (see Chapter 7) to remain loosely coupled with the backend, allows details of the backend (e.g., data dependencies) to be abstracted from modules, and gives modules the flexibility to work with any set of data that contains what the data interface requires. In teams where web developers and backend engineers are separate roles, these qualities let each role work independently, knowing that both are working toward a common point where the user interface and backend will ...