The main problem is moving very large databases from one system, for example, to transfer critical data from Oracle to SQL Server. Several issues need to be considered, such as loss of transmitted data, data security, costs and effort, technical aspects of software, etc. There are very few books that provide practical tools and methodology for migrating databases from one manufacturer to another. This book introduces the concepts of database migration with large examples. It provides step-by-step guides and screenshots for database migration tools. Many examples are provided for migrating Oracle, SQL Server, and MySQL databases.