How does the document-db nature come up in practice? For example are transactions single-document in Crux? I'm trying to understand the difference in semantics and data model vs Datomic.
Documents are best thought about in terms of being the unit of ingestion and history - they do not have strong implications for queries asides from having a 1:1 mapping with entities.
Each transaction may contain multiple operations and each operation is typically only relating to one document. A document represents a single version of an entity and is decomposed during ingestion into an arbitrary set of attribute-value datoms that get updated atomically and fully replace all the previous attribute-value associations of the given entity.
Something not mentioned in the post is that there is a Java API in addition to HTTP and Clojure.
The Beta programme is commencing very early in 2020 - please contact us in the meantime if you are interested to hear more: crux@juxt.pro