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@thegeez
Created December 18, 2012 19:56
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;; bin/repl with datomic-free-0.8.3664
(use '[datomic.api :only [q db] :as d])
(def uri "datomic:mem://future")
(d/create-database uri)
(def conn (d/connect uri))
;; balance attr
@(d/transact conn [{:db/id (d/tempid :db.part/db)
:db/ident :account/balance
:db/valueType :db.type/long
:db/cardinality :db.cardinality/one
:db.install/_attribute :db.part/db}])
;; create entity
(def eid (-> @(d/transact conn [{:db/id (d/tempid :db.part/user)
:account/balance 100}])
:tempids
first
val))
;; async happy path
(def ta1 (d/transact-async conn [[:db.fn/cas eid :account/balance 100 200]]))
(prn "ta1 result: " @ta1)
(prn "account balance: " (:account/balance (d/entity (db conn) eid)))
;; => 200
;; async fail path
(def ta2 (try (d/transact-async conn [[:db.fn/cas eid :account/balance 400 500]])
(catch Exception e
(prn "Won't get to here: " e))))
(try @ta2
(catch Exception e
(prn "Should end up here:" e)))
;; sync happy path
(def t1 (d/transact conn [[:db.fn/cas eid :account/balance 200 300]]))
;; can get the response
(prn "t1 result: " @t1)
(prn "account balance: " (:account/balance (d/entity (db conn) eid)))
;;=> 300
(def t2 (try (d/transact conn [[:db.fn/cas eid :account/balance 400 500]])
(catch Exception e
(prn "Should not get here, but somehow do: " e))))
(prn "t2 did not return a future")
;;;; this should have worked:
;;(try @t2
;; (catch Exception e
;; (prn "Wanted to check this way.")))
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