PHP and MySQL for Dynamic Web Sites: Visual Quickpro Guide, Second Edition

Using Sessions

Another method of making data available to multiple pages of a Web site is to use sessions. The premise of a session is that data is stored on the server, not in the Web browser, and a session identifier is used to locate a particular user’s record (session data). This session identifier is normally stored in the user’s Web browser via a cookie, but the sensitive data itself—like the user’s ID, name, and so on—always remains on the server.

The question may arise: why use sessions at all when cookies work just fine? First of all, sessions are more secure in that all of the recorded information is stored on the server and not continually sent back and forth between the server and the client. Second, some users reject cookies or ...