Founder @ PipelineDB here (hi Slava!) Currently continuous views must read from a stream. However, in the very near future it will possible to write to streams

Founder @ PipelineDB here (hi Slava!) Currently continuous views must read from a stream. However, in the very near future it will possible to write to streams from triggers, which would probably give you enough flexibility to model the behavior you want if you could conceptualize a table as a stream of changes.