Great that this now free for small projects. I've been pondering two questions about Datomic: (1) immutable data is great, but what if we have to delete some past data, for privacy or regulatory reasons? Does this screw everything up? (2) can we modify values as-at past points in time? Example, an electricity company records usage monthly for customers, but sometimes past usage is incorrect and needs to be edited. What would be the best way to structure this to get the "updated" view as-of six months ago? And also the "original" view as-of six months ago?
>> (1) immutable data is great, but what if we have to delete some past data, for privacy or regulatory reasons? Does this screw everything up?
I recall reading about the ability to clear out old transactions, to account for fast-growing databases. For example, "delete all transactions and facts older than 2 months". 2 minutes of googling didn't yield any results though, sorry.
>> (2) can we modify values as-at past points in time? Example, an electricity company records usage monthly for customers, but sometimes past usage is incorrect and needs to be edited. What would be the best way to structure this to get the "updated" view as-of six months ago? And also the "original" view as-of six months ago?
If I understand you correctly, you do this by adding a new fact with the correct usage. Your queries will now return the latest number, and you can use `as-of` and so on to get the old value.
