Session saves data on the server side, and each user has his own session, which does not conflict with others'.

In other words, after you log in to the system, your information (such as account number, password, etc. ) will be saved in a separate session on the server. When you log off the system, the server will lose this session and your data will be lost. You must log in again. If you log in overtime, you will lose it, depending on how the system is set up.

Cookies, like session, save your personal information, but they will not be lost when stored on the client, that is, the computer you use, unless you delete the browser Cookie.

Caching is to save information on the system, because it is faster to read data from the cache, so some systems (websites) will put some commonly used data into the cache to improve access speed and optimize system performance.

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