Sometimes in the event of a service failure, a mysql database can become corrupted due to a partial save or lack of a save when the crash occurs. When this occurs, you may see errors (depending on the type of scripts you're using on your site) that show mysql errors or perhaps errors connecting to your database.
Normally this can be sorted by running a repair on the database in question in cPanel. To do this:
1. Login to cPanel and click on the "MySQL databases" icon.
2. Select the database you'd like to repair under the "Modify Databases" section under "Repair Database" field. [See below]
3. Click the "Repair Database" button.
Depending on the size of your database, that could take a few seconds to a minute or more to run. It will give you the results once completed.