Is there a particular reason why you don't want to make your database changes in PHPMyAdmin? The examples of data manipulating you describe can be done through the Operations and Structure tabs of PHPMyAdmin. Text replacement within tables (even using regular expressions) can be done through SQL queries.
In my experience, manipulating databases through text files can quickly lead to errors in the database. -- <http://forum.pspad.com/read.php?2,49866,49882> PSPad freeware editor http://www.pspad.com
