Database as a Service Benefits
Platform as a Service (PaaS) database offerings such as Azure SQL are rapidly becoming a popular option for organizations deploying databases in the cloud.
One of the benefits of Azure SQL, which is essentially a Relational Database as a Service (RDaaS), is that all of the database infrastructure administrative tasks and maintenance are taken care of by Microsoft – and this is proving to be a very compelling value proposition to many Imperva customers.
Security is a Shared Service
What you should remember with any data migration to a cloud service, is that while hardware and software platform maintenance is no longer your burden, you still retain the responsibility for security and regulatory compliance. Cloud vendors generally implement their services in a Shared Security Model. Microsoft explains this in a whitepaper you can read here.
To paraphrase in the extreme, Microsoft takes responsibility for the security of the cloud, while customers have responsibility for security in the cloud.
This means Microsoft provides the services and tools (such as firewalls) to secure the infrastructure (such as networking and compute machines), while you are responsible for application and database security.
Though this discussion is about how it works with Azure SQL, the table below from the Microsoft paper referenced above shows the shared responsibility progression across all of their cloud offerings.