A method and apparatus for transactions during a data migration. The transfer of data from an old database to a new database is structured as a set of small transactions. The transactions can be structured in a hierarchy of dependent transactions such that the transactions are nested or similarly hierarchical. A migration manager includes a set of data conversion methods or processes that enable the conversion of data from a format of an old database to that of a new database. The conversion process generates the nested transactions to resolve dependencies between records such as primary and foreign keys. The method and system provides a higher level of granularity in transaction size, providing the ability to transfer records individually and resolve the dependencies in such transactions without requiring a large mapping of an entire data set in the old database to an organization in the new database.