myfoot, apparently you don't like to look up things yourself. I have looked at your previous posts and your questions are always very general with no details of what you're trying to do. Also, the questions you ask show that you don't use search engines or know how to use the manual pages in Linux. So instead of giving you the answer to your question, I am going to show you how YOU can find it yourself. At least show some initiative and people would be more happy to help you. Most posts answering your questions are links to web sites found on google or references to man pages.
To use google:
go to http://www.google.com
type a search phrase in the box. for this question, a good phrase might be 'mysql database rename'
Press the 'Google Search' button. Look through results to see if they solve your problem.
If they don't solve your problem, try different search phrases.
If that still doesn't solve your problem, post here and let us know what you've tried and any info/data that may help us find and answer
To use man pages:
on Linux command line, type 'man <program>' where <program> is the name of the program you need help with.
I don't mean to sound harsh, but it bothers me when people don't at least make an effort to do something themselves.