You don't need a full account backup to protect or restore one database. Use phpMyAdmin's Export and Import tabs for a straightforward backup, or mysqldump and mysql over SSH if you want something scriptable. Both work on a single database without touching the rest of your account.
Backing up with phpMyAdmin
Open phpMyAdmin from the portal (Services → your hosting → phpMyAdmin, one-click login). Select the database in the left sidebar, click the Export tab, choose Quick export method and SQL format, then click Go. Your browser downloads a single .sql file containing every table, row, and the structure needed to rebuild it.
For a large database, switch to Custom export method. It lets you exclude specific tables or skip data and export structure only.
Backing up with mysqldump over SSH
If you have SSH access, mysqldump works well for large databases and can be put in a script:
mysqldump -u dbuser -p dbname > dbname-backup.sql
Replace dbuser with a database user that has access to dbname, and dbname with the actual database name (check MySQL Databases in the portal or Manage My Databases in cPanel if you're not sure of the exact name). You'll be prompted for the password. To compress the output directly:
mysqldump -u dbuser -p dbname | gzip > dbname-backup.sql.gz
Restoring a database
In phpMyAdmin, select the target database (create a new one first via MySQL Databases in the portal if you're restoring into a fresh database), click Import, choose your .sql file, and click Go. phpMyAdmin runs the file as a series of SQL statements, recreating tables and reinserting data. Large files can hit PHP's upload limit before they hit phpMyAdmin's own import limit; if the import fails partway through with no clear SQL error, that's a likely cause.
Over SSH, restoring is the reverse of the dump:
mysql -u dbuser -p dbname < dbname-backup.sql
For a gzip-compressed dump:
gunzip < dbname-backup.sql.gz | mysql -u dbuser -p dbname
The target database must already exist and the database user must have privileges on it before you run either command. mysql doesn't create the database for you.
If the import is too large for phpMyAdmin
Compress the file with gzip before uploading through phpMyAdmin's Import tab. It accepts .sql.gz directly and decompresses on the fly, which usually gets you under the upload ceiling without needing SSH at all. If it's still too big, that's the point to switch to the SSH method above or open a ticket.
Restoring from a WordPress site instead
If the database belongs to a WordPress install and you just need to undo recent changes rather than restore a specific export, your site's own backup plugin or tool may be faster than the manual export/import steps above, depending on what you have set up.
When to contact support
If an import fails with a cryptic SQL error, the database user's privileges look right but access still fails, or you need a database restored from a point in time you didn't manually export, open a ticket from Support in the portal. A real person will look into it and help you figure out the options.