Defining Static and Dynamic Data

Web applications can include the concept of static and dynamic data. Dynamic data is the best type to use for Web services because it reflects changes in the Google database. An application gains important benefits by using dynamic data. For example, you won't try to access an old Web site that Google used to list because the dynamic nature of your application automatically removes the link from the list of results.

Unfortunately, dynamic data can also cause problems. For one thing, you need a connection to the Internet to work with dynamic data. When you use a desktop machine, maintaining a connection usually isn't a problem. However, many third party developers are working on applications where a connection might not be available, such as a research list application for a PDA. You download the information from Google Web Services and then use it to create a report while on the road—the connection doesn't exist while you're on the road so the data is no longer dynamic.

Note Google does support the concept of cached data that is stored from the original Web site, but even the cached data ages at some point and becomes unavailable. Cached data does have an important use. For example, you can use cached data to obtain copies of old articles that a Web site no longer carries.


Using the term dynamic to refer to application data is also somewhat of a misnomer. Nothing is truly a dynamic data application. The moment the response to your query leaves the Google server, it begins to age. The data doesn't change once it leaves the Google server, so in reality it isn't truly dynamic. The only way you can achieve a dynamic presentation of sorts is to make multiple queries. You must define how often is often enough for your needs. Google doesn't provide any guidance in this case because search result viability varies by person, focus, and need.

These facts lead into the discussion of static data. Truly static data never changes at all. Most Web sites still rely on static data presentation because the information they display doesn't change often enough to warrant a dynamic presentation. When you make a single query to Google Web Services, the response you receive is static data. It's a snapshot of that particular part of the database at a specific time. The data won't change unless you make another query.

Understanding the static and dynamic nature of data is important when you design an application that relies on Google Web Services. Errors creep into the presentation you create as the data from Google Web Services ages on your system. Part of the design process for your application is to determine how much error you can accept.