I recently had to migrate my database on 1and1 hosting from MySQL 4.0 to MySQL 5.0 and their instructions and a lot of the internet’s instructions were pretty incorrect. So here is the right way to do it.
1. Go to the “MySQL Administration” area of your hosting provider.
For 1and1, just login and under the “Web Space” click on the link “MySQL Administration”.
2. Create a new MySQL 5.0 database for WordPress to use.
3. Update your wp-config.php file to use the new database’s name, username, password, and hostname.
4. In the MySQL Administration area, find and click on a link for phpmyadmin for your old database.
5. Once you are in phpmyadmin, click on the databases name in the left hand column. It does not look like a link, but it is.
6. After clicking on the databases name, the right-hand column of the page should update with some tabs. Click on the top tab labeled “Export”.
7. Under the “Export” heading select all the tables in the export box so they are all highlighted. Then check the checkbox at the bottom to “Save as file” and select the “gzipped” radio button option. Then save the gzipped file locally.
8. Go back to the MySQL administration area and click to use phpmyadmin for the new MySQL 5.0 database you setup.
9. Once you are in phpmyadmin for the new database, click on the databases name on the left. Again, it does not look like a link, but it is.
10. The right hand coolumn shoudl update again with tabs at top, click on the “SQL” tab.
11. At the bottom you should see an area title “Or Location of the text file:” with a choose file button. Click on the button to choose the gzipped file you exported locally earlier. Then select the “gzipped” option for compression, and then click the “Go” button.
12. Visit your blog’s URL and WordPress might have to update the database automatically for you. Just agree if it asks to.
#12 might be because I updated to the newest version of wordpress when I did this as well. To update your version of wordpress, just go to wordpress.org, download the latest version. Unzip the files, and just copy and paste the files over your old wordpress files. Don’t forget to update the wp-config.php with your new database credentials.