no-history.clj

;; find all historic :gateway/last-seen attribute for an entity

(d/q '[:find ?v
       :in $ ?e
       :where [?e :gateway/last-seen ?v]]
     (d/history (d/db conn))
     17592186045459)

#{[#inst "2015-08-12T09:52:53.716-00:00"]}

;; note that the attribute has noHistory set to true

(d/pull (d/db conn) '[*] :gateway/last-seen)

{:db/id 73
 :db/ident :gateway/last-seen
 :db/valueType {:db/id 25}
 :db/cardinality {:db/id 35} ;; :db.cardinality/one
 :db/noHistory true}

;; make a new request, resulting in an updated :last-seen attr

(d/q '[:find ?v
       :in $ ?e
       :where [?e :gateway/last-seen ?v]]
     (d/history (d/db conn))
     17592186045459)

#{[#inst "2015-08-12T09:54:08.737-00:00"] [#inst "2015-08-12T09:52:53.716-00:00"]}

;; now there are two entries in history

;; why? how?