Cloud computing is rapidly becoming an important platform for research in Software Engineering. Despite the vibe and huge literature on commercial Cloud environments, there is, however, little research on how to capture, model, design and implement new software applications that can make intelligent use of the Cloud. In this paper we propose a new abstraction that explores a fundamental aspect of Cloud systems – data elasticity. The Container Database (CDB) abstraction provides a Cloud-based solution for scenarios where device local storage is not sufficient for manipulating data. To demonstrate the viability of the proposed approach we present an implementation of the CDB abstraction as an Object-Oriented API designed to work on Windows 7 and Windows Mobile Phone 7 Operation Systems.