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@DaveWM
Created November 21, 2019 17:17
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Datomic - update cardinality many attr
(ns datomic-update-cardinality-many
(:require [datomic.api :as d]))
(defn update-attr-txs [db entity-id attr values]
(let [current-vals (-> (d/q '[:find [?p ...]
:where [?id :intention/parents ?p]
:in $ ?id]
db
entity-id)
(set))
[added removed] (clojure.data/diff (set values) current-vals)]
(concat (->> added
(map #(-> [:db/add entity-id attr %])))
(->> removed
(map #(-> [:db/retract entity-id attr %]))))))
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