What Is Session State Management?

Earlier in this book, you learned about how FORM and URL variables can be used to pass variables from one page to another. Later, in the chapter on custom tags, you will learn of a tag called <CF_EmbedFields>, which allows you to simulate the passing of form variables across multiple pages. Although these techniques leave the impression of state maintenance, they are, at most, a poor man's version of it.

URL and FORM variables were discussed in Chapters 8 and 9, respectively. Custom tags are discussed in Chapter 28, "Custom Tags."

True state maintenance requires that information be stored in a way such that it exists outside the scope of variables that must be passed manually from page to page.

In the previous chapter, you learned about APPLICATION and SERVER variables. These are true state-maintenance variables that are saved in the server's memory.

APPLICATION and SERVER variables were discussed in Chapter 10, "APPLICATION and SERVER Variables and SERVER Variables."

In this unit we learn about three more state-maintenance variables: COOKIE, SESSION, and CLIENT. The difference between these variables and APPLICATION and SERVER variables is that these are used specifically to maintain state about one user, rather than just information that is global to the application or server.