http://www.magentocommerce.com/wiki/1_-_installation_and_configuration/db-repair-tool
Install the same version of Magento you’re using into a
clean database. Use the new database as “reference” and the current database as “corrupted”.
clean database - чистая БД
Step-by step
Download Magento database repair tool archive from the download page
Uncompress the archive
Put the magento-db-repair-tool-1.0.php into any folder on your server
Backup your existing database to have ability to restore it if anything goes wrong
Clone it as new database on the same server. Let’s call it “database2”
Create an empty database (”database3”)
Either copy your entire Magento folder (without cache and sessions) into a new one and install there into “database3” (By editing local.xml with credentials for the newly created “database3”);
Or if you already restricted access to your Magento instance, you may just change your database credentials into “database3”, clean cache and launch Magento once: it will be installed automatically.
Create an empty database (”database3”) - создать пустую БД.