[saxenaabhi]

> Any modern DB with a WAL (write ahead log) is an immutable event system, where the events are the DB primitives (insert, update, delete...).

Agreed, I just wish apart from WAL they also had versioning as first class and their update api required clients to pass the version they have "last seen" to prevent inconsistencies.

[javcasas]

On most SQL databases, you can put CHECK constraints on columns so that the database rejects events. But this is controversial, as people don't like putting logic on the DB.

[serbrech]

CosmosDB has etags on every document