Oracle offers various cloud database services that provide different levels of automation, availability, and pricing depending on customer requirements. These include Exadata Express for small test/development databases, Oracle Database Virtual Machine for OLTP workloads up to 12TB, and Exadata Cloud Service for mission critical environments up to 1.5PB. Oracle cloud databases provide high availability across regions and availability domains. The Autonomous Database option provides full automation for backups, patching, and tuning. Migration from on-premises to Oracle cloud databases can use various methods while maintaining high availability. Oracle cloud databases provide more full-featured options compared to other clouds, but some capabilities require more manual configuration outside of Oracle cloud.