They have completely different data models though, XTDB is a schemaless document data store, think mongodb but with SQL/Datalog querying and bi-temporality. Da

They have completely different data models though, XTDB is a schemaless document data store, think mongodb but with SQL/Datalog querying and bi-temporality. Datomic's data model is something they call the 'universal schema' where you just specify the attributes and then create entities however you like from them. Datomic aligns more with how you structure data in Clojure, avoiding the impedance mismatch.