Abstract. The concept of Cloud Computing is by now at the peak of public attention and adoption. Driven by several economic and technological enablers, Cloud Computing is going to change the way we have to design, maintain and optimise large-scale data-intensive software systems in the future. Moving largescale, data-intensive systems into the Cloud may not always be possible, but would solve many of today's typical problems. In this paper we focus on the opportunities and restrictions of current Cloud solutions regarding the data model of such software systems. We identify the technological issues coming along with this new paradigm and discuss the requirements to be met by Cloud solutions in order to provide a meaningful alternative to on-premise configurations.