Hello,

In order to update an entry in your database, you need to use an UPDATE statement.

So let’s say that you have a table called users and a column called nickname and you want to change the entry for a user with nickname DigitalOcean to DO, you could do that with this query:

UPDATE users SET nickname = 'DO' WHERE nickname = 'DigitalOcean';

Of course, if you are unsure, always make a backup of your database first!

I would recommend having a look at this tutorial on how to install and also use a PostgreSQL database:

https://www.digitalocean.com/community/tutorials/how-to-install-and-use-postgresql-on-ubuntu-18-04

Also you could go through some of the PostgreSQL tutorials here:

https://www.digitalocean.com/community/tags/postgresql?type=tutorials

Hope that this helps!
Regards,
Bobby