This can be solved in different ways. First, everything is an entity, so you can enrich attributes with information about how they should manage PII/SPI data.

This can be solved in different ways. First, everything is an entity, so you can enrich attributes with information about how they should manage PII/SPI data. There's nothing built-in but you can build meta models easily. Second, if you really have stringent requirements you would encrypt the data that is to be protected and throw away the encryption keys when the data needs to be purged. Datomic does allow you to opt out of history so the keys would not be recoverable in that case. Or, you just excise the data, at which point the information will be purged from the database. It's not instant, index rebuilds and garbage collection need to take place before it's really gone. You're in control. The fact that you have history isn't a problem.