Part 5: Managing Sessions

What is a Session Variable?
Session variables are similar to cookies, that is they are used to store information for a particular period of time. The values in session variables exist only till the session exists. They are used to carry information from one page to another of a web site. We can create a session using a session identifier and store it in the server. When the client makes any request, the data stored in the session variable can be accessed by PHP any number of times until the session is ended.

Why do we need a Session Variable?
In web sites, passing information between pages using a query string is very difficult. For example once you log into a site, passing the username to all the pages of the site using query string is very difficult, but this can be done easily using Session variables. These variables can be used to pass information from one page to another without using a query string, since it is easy to maintain and retrieve.

How to set Session Variables?
Session variables can set using 'session_register' function.