Differences and usage between mysql and mysqli

Differences and usage between mysql and mysqli

Mysql is a non-persistent connection function, while mysqli is a permanent connection function. That is to say

Mysql opens a connection process at each link, and mysqli runs mysqli multiple times to use the same connection process, thus reducing the server overhead.

When programming, some friends always use new mysqli ('localhost', usenamer ', 'Password', 'databasename'); there is always an error, Fatal error: class 'mysqli' not found in d :...

Isn't the mysqli class included in php?

It is not enabled by default. In win, you need to change php. ini and remove the ones before php_mysqli.dll. in linux, You need to compile mysqli.