Data migration
Post-migration: After data migration, results are subjected to data verification to determine whether data was accurately translated, is complete, and supports processes in the new system. During verification, there may be a need for a parallel run of both systems to identify areas of disparity and forestall erroneous data loss. Additional documentation and reporting of the migration project is conducted, and once the migration is validated complete, legacy systems may also be decommissioned. Migration close-out meetings will officially end the migration process.
Data transformation
Data mapping is the process of defining how individual fields are mapped, modified, joined, filtered, aggregated etc. to produce the final desired output. Developers or technical data analysts traditionally perform data mapping since they work in the specific technologies to define the transformation rules (e.g. visual ETL tools, transformation languages).