DB Replacer enables you to search and replace in any table in your database.
It even supports searching with case sensitivity.
Sometimes you need to replace something in all your articles. That takes hours doing it the conventional way: open article, change, save article, open next article, etc...
With DB Replacer this takes a few seconds.
DB Replacer gives you a preview of what is going to be replaced, so you know what you are doing before actually replacing anything.
WARNING: DB Replacer replaces stuff right in your database in the places you tell it too. This can - if you replace the wrong stuff - break your site. So be careful and only use this if you know what you are doing.
How to use it: http://www.nonumber.nl/dbreplacer
NoNumber extensions require php 5.3+
See for more requirements: http://www.nonumber.nl/dbreplacer#requirements