All terms
Glossary
Data migration
Moving existing data into a new system, usually the underestimated and most schedule-critical part of a replacement.
Migration has three parts: transfer, transformation and reconciliation. Reconciliation decides the date, because it answers whether everything is still there afterwards.
On top come records that the old model allowed and the new one does not: empty mandatory fields, duplicate keys, dates in the future.
How you notice it
- Data is moving to a new system or a new schema.
- Old records contain formats nobody documented.
- The cutover window is short.
Frequently asked
What is usually underestimated?
Data quality. Every migration surfaces records that violate rules the new system enforces: missing fields, impossible dates, duplicates. Counting these before the cutover, not during it, is the difference between a night and a weekend.