Example code for 'load-entities'

load-entities-example.clj

(require '[datahike.api :as d])

(def schema [{:db/ident       :name
              :db/cardinality :db.cardinality/one
              :db/index       true
              :db/unique      :db.unique/identity
              :db/valueType   :db.type/string}
             {:db/ident       :sibling
              :db/cardinality :db.cardinality/many
              :db/valueType   :db.type/ref}
             {:db/ident       :age
              :db/cardinality :db.cardinality/one
              :db/valueType   :db.type/long}])

(def cfg {:store  {:backend :mem :id "sandbox"}
          :keep-history? true
          :schema-flexibility :write
          :initial-tx schema})

(d/delete-database cfg)

(d/create-database cfg)

(def conn (d/connect cfg))

(def entities
  [[1000 :db/txInstant #inst "2020-11-18T09:30:20.275-00:00" 1000 true] ;; tx meta data
   [100 :name "Alice" 1000 true] ;; normal entity
   [100 :age 25 1000 true]
   [1001 :db/txInstant #inst "2020-11-18T09:35:20.122-00:00" 1001 true]
   [101 :name "Bob" 1001 true]
   [101 :age 35 1001 true]
   [1002 :db/txInstant #inst "2020-11-18T09:35:25.459-00:00" 1002 true]
   [100 :age 25 1002 false] ;; entity updates in history
   [100 :age 30 1002 true]
   [1003 :db/txInstant #inst "2020-11-18T09:36:11.765-00:00" 1003 true]
   [102 :name "Charlie" 1003 true]
   [102 :age 45 1003 true]
   [102 :sibling 100 1003 true] ;; references
   [102 :sibling 101 1003 true] ;; many cardinality
   ])

@(d/load-entities conn entities)

(d/q '[:find (pull ?e [* {:sibling [:name]}] )
       :where
       [?e :name _]] @conn) ;; check data with new IDs

(d/q '[:find ?n ?a ?d ?added
       :where
       [?e :name ?n]
       [?e :age ?a ?t ?added]
       [?t :db/txInstant ?d]]
     (d/history @conn)) ;; check changes in history