What are the three service models that provide the foundation to service-oriented DSS? How does DaaS change the way data is handled? What is MaaS? What does it offer to businesses? Why is AaaS...

What are the three service models that provide the foundation to service-oriented DSS? How does DaaS change the way data is handled? What is MaaS? What does it offer to businesses? Why is AaaS cost-effective? Why is MapReduce mentioned in the context of Aaas?