Problem with mysql,php on Centos 7

I’m a beginner and I’m trying to install Ojs 3.1.1-4.
But the graphic installer not work namely i put all the fields however it brings me back to the beginning, then i try to install within tools in the terminal and at the end the following error appeared
uncaught error: Call to undefinerd functions mysql_connect in /var/www/html/ojs/lib/pkp/adodb/drivers/ 456
Any advice