I have a Laravel application. It's live and have daily users. I need to update some features. Not only front end work. Have to change back end too. With database. The problem is our old developer created this site. Now he's not here, and also no any documentation or blue print available. I downloaded the project. I can change front end even it's live. Changes affected. Is there any way to change some back end and database when it's live ? Is that a risk ? Please guys don't give minus points to this question.
You should be creating a development environment on your local machine, with it's own database etc. Change that, test it, and once you are happy, upload your file and schema changes.
For setting up a quick dev environment that closely matches your production server, download VirtualBox and Vagrant. Then visit http://puphpet.com, which will allow you to generate a server config.
Unzip the config, cd into the folder, and type vagrant up. Your server is now on 192.168.56.101.
Lastly, edit your OS hosts file to point your.dev.site.com to that ip. (the default domain name in puphpet is awesome.dev
You can get inside the VM by typing vagrant ssh if you need to.
Don't edit a production site, especially with live users!