1. A database migration system, comprising: one or more processors; and memory storing a plurality of integrated programs for execution by the one or more processors, one of the plurality of integrated programs including: a first connection to a relational database; a second connection to an in-memory database; a migration framework to analyze the data structures of the relational database so as to identify first and second subsets of data structures, wherein the first subset of data structures is migrated to the in-memory database during an uptime period of the relational database, and the second subset of data structures is migrated to the in-memory database during a downtime period of the relational database.