Numerous heterogeneities among different local databases and cloud storages make database migration to the cloud an interesting and complex research and practical problem. Successful execution of more complex interoperability scenarios cannot be imagined without being able to move data from local servers to the cloud, and from one cloud storage to another. In this work, the authors have developed a working prototype of a migration tool for MySQL, PostgreSQL and Microsoft SQL Server. The main contribution of this work is the identification of problems that can occur during database migration process to the cloud. The authors also list differences between data storage models of various commercial cloud providers to envisage possible issues when moving data from one cloud storage to another.