Normally when you update a row in a database you lose the ability to access the previous values. E.g. If you update your address it overwrites your previous add

Normally when you update a row in a database you lose the ability to access the previous values. E.g. If you update your address it overwrites your previous address With datomic you are just adding a new fact. My address is now x. This has a lot of nice properties. I can now easily write a query to tell me your previous 5 addresses, rolling back is easy, you can get amazing and scalable read performance, etc etc In the past we have either had to hand roll our own features (e.g. Have a table of past addresses, or add date columns to specific tables) or rely on error prone/brittle techniques like using audit tables, source control, or transaction logs. Datomic makes it easy!