Changing The Site URL
WordPress stores two addresses inside the database. These determine where your blog files are, and where the main index is. On a normal install, these addresses are the same.
There are two occasions where you will need to access the database to alter one or both of these settings:
1. If you have tried to alter the Blog URL or WordPress URL in Settings, and an error has occurred.
2. If you have moved to a domain/subdomain with a different name.
BACKUP your database before you begin and store the backup off your site server, like on your hard drive. See: Backing Up Your Database.
Quick fix method
If you have access to the site via FTP, then this method will help you quickly get a site back up and running, if you changed those values incorrectly.
1. FTP to the site, and get a copy of the active theme’s functions.php file. You’re going to edit it in a simple text editor (like notepad) and upload it back to the site.
2. Add these two lines to the file, immediately after the initial “
update_option(’siteurl’,'http://example.com/blog’);
update_option(’home’,'http://example.com/blog’);
Use your own URL instead of example.com, obviously.
3. Upload the file back to your site, in the same location. FileZilla offers a handy “edit file” function to do all of the above rapidly, if you can use that, do so.
4. Load the login or admin page a couple of times. The site should come back up.
5. Repeat the above steps, but remove those lines. IMPORTANT: Do NOT leave those lines in there. Remove them immediately after the site is up and running again.
If there is no functions.php file in the theme: Create a new text file called “functions.php”. Edit it with notepad, and add this text to it, using your own URL instead of example.com:
update_option(’siteurl’,'http://example.com/blog’);
update_option(’home’,'http://example.com/blog’);
Upload that to your theme directory, then proceed as stated above. Remove the file afterwards.