PaaS is the most suitable service model would be used for a database in the cloud. IaaS is of course can be used to bring up instances and then install database application on top of those instances. However, this approach does not utilize full advantages and benefits of cloud computing. The administrators have to manage and maintain all necessary infrastructure that can be offload by PaaS solution. Example: Azure SQL Database is a fully managed platform as a service (PaaS) database engine that handles most of the database management functions such as upgrading, patching, backups, and monitoring without user involvement. SQL Server on Azure Virtual Machines (VMs) is an IaaS offer and allows you to run SQL Server inside a virtual machine in the cloud.