Restoring Your Drupal Database

By Lynn Beighley and Seamus Bellamy from Drupal For Dummies, 2nd Edition

Should you ever lose your Drupal data and have to restore your database, the following provide you with the basic steps for that restoration. You should consult your web host's documentation for specific instructions on restoring a database. There's a good chance that you won't have the appropriate permissions, and the following instructions won't work for you. If you do have the appropriate permissions, follow these steps:

Using the phpMyAdmin application, choose the Drupal database from the list of database names in the left pane.
Click the Operations tab.
Type a name into the Rename Database To text box and click Go.

Your new database will have the same name as your old one, so you need to save your old one with a new name. You’ll delete the old database when you’re done.

Your web host may have restricted you from deleting databases. If this is the case, this step will fail. Be sure to contact your web host’s support staff to let them know that you need to restore your database — and send them the backup file.
Click the Import tab.
Browse to the location of the database .zip file containing your Drupal database backup and select it. Click Go.

Your database is restored.