You have to have a unique identifier on the row from the Database.
Then you have to get the data from the DB on click into a form to edit it.
Then all you have to to is to update the DB with your new values, if there are new values.
You'd implement the button function on the front end of your application . At the database end, you'd need to connect to your database and update your table by using an sql upadte query syntax:
SET [column_name] = value, [column_name2] = value2,..
WHERE [_column_name] = _value
The words in braces are variables, i.e they depend on your own values. I assume you're familiar with simple SQL operations too. If not, no worries, they're quite easy to learn. A number of sites are available on the net. Check out w3schools.com as a starter.