WordPress DBC Backup give you a simple way to schedule daily database backups using the wp cron system. You can select when and where your backup will be generated. If your server has support you can select between three different compression formats: none, Gzip and Bzip2. The plugin will try to auto create the export directory, the .htaccess and an empty index.html file to protect your backups. The backup file is also protected by a small hash key which make it impossible for someone to guess the backup name and download it.

You can get DBC Backup plugin from here