I have trouble trying to secure my website by changing prefix

that means this key has already been updated

That means I dont have to do anything ? Its all done ?

yes, try accessing your site.. especially creating a new user, login with that user .. if all this works fine, you are already done..

Thank you.

I have been fiddling with this for the past hour.

Now I have moved on to editing the wp_usermeta, suddenly my whole databank got wiped out !

I am now requesting for my host to help me restore my backup as we speak.

Can you please tell me the possible cause of this ? How can I safely do this the next time ?

Is there a plugin which can allow me to secure wordpress without going through this ?

1) next time, take a full backup of your database ??
2) In phpmyadmin or some other tool, search for wp_ in your database, and replace it at all possible places, especially mentioned here

It is always better to do this before install, rather than changing afterwards… ??

There is no magic plugin that can change everything in one go ? =(

https://www.seoegghead.com/software/wordpress-table-rename.seo

Thank you very much, I shall try this once I got my site backed up =)