hi ThachPham, this solution takes care of different config settings on your local and live websites, and a staging test site if you have one. It doesn't take care of the database itself, however.

I use it for things like database login details, debug mode, anything that you want to be different between your local test site and your live one. It also takes care of the site URL in the WordPress database so you don't need to hack that in the database when going live.

You're quite right, you need to copy your database from local to your live environment too. I usually work on a local copy of the site while building a site so when I'm ready to review this on staging or live I'll just copy the DB up to the live website (via SQL dumps). If you have database connection settings correctly setup in the multi-environment config it should then just work.

Maybe there's a need for easy database synching too! But I think there are a few solutions out there already like WP Migrate DB https://wordpress.org/plugins/wp-migrate-db/