savings. The term, Cloud Computing was first used in 1997 at Ramnath Chellappa’s lecture, when he defined it as "a computational paradigm where computational limits will be determined by economic reasons and not technical limitations".
Fig. 1. Proposal for the Graphical Representation of a Cloud
The essence of the Cloud Computing concept is mainly in terms of hardware, with deep consideration to software also, because the processing power is moved on the Internet. Thus some servers placed at addresses unknown by the user bring processing power without physical possession, but only virtually by renting their computation and storage capacity. The Cloud Computing evolution in the latest years is one of the greatest advances in computing history. Given that this technology will reach its potential in several years, we must have a sound understanding of technology both in terms of consumer and provider. Cloud Computing is making a lot of advances into all aspects of IT. Databases in the Cloud will experience major architectural changes to take advantage of massive scalability and large amount of data. A product which was released by Oracle especially for database control on the Cloud is Oracle Enterprise Manager 12c. This tool is known for “creating business value from IT by leveraging the built-in management capabilities of the Oracle stack for traditional and cloud environments, allowing customers to achieve unprecedented efficiency gains while dramatically increasing service levels.”[8] Although many studies are now based on the technology itself, there is a great need for research of the business implications for cloud adoption. In this paper we describe the key issues for understanding the concept of cloud computing. Cloud service models The Cloud Computing concept is strictly defined in this article through the services of three models. The service model describes an approach whereby the cloud supplier aim to satisfy clients’ demands. Cloud Computing provides functionality to users as a service. This technology changes the angle that we were looking upon software and hardware. The owner of a business should not invest in physical devices. Thus, he must use cloud resources as an alternative solution through pay-as-you-go payment method so he can pay only the resources that he needs. The system recognizes subsequent requests and provides customer the performance they require. Although all cloud services work in the same way they differ in the abstraction level, thus being classified in the following 3 types of services: Software as a Service (SaaS), Platform as a Service (PaaS) and Infrastructure as a Service (IaaS). [6]