hrm.clj

; asserting cardinality many ref values using lookup refs appears not to work:

 {:db/index true,
  :db/unique :db.unique/identity,
  :db/valueType :db.type/string,
  :db/noHistory false,
  :db/isComponent false,
  :db.install/_attribute :db.part/db,
  :db/fulltext false,
  :db/cardinality :db.cardinality/one,
  :db/doc "",
  :db/id {:part :db.part/db, :idx -1000058},
  :db/ident :variant-context/id}

 {:db/index false,
  :db/valueType :db.type/ref,
  :db/noHistory false,
  :db/isComponent false,
  :db.install/_attribute :db.part/db,
  :db/fulltext false,
  :db/cardinality :db.cardinality/many,
  :db/doc "",
  :db/id {:part :db.part/db, :idx -1000273},
  :db/ident :sample/variant-contexts}

@(d/transact conn [{:db/id (d/tempid :db.part/user) :variant-context/id "foo"}])
=> {:db-before datomic.db.Db@d0cd4c4d, :db-after datomic.db.Db@9bbff236, :tx-data [#datom[13194139534318 50 #inst "2015-11-30T20:28:32.309-00:00" 13194139534318 true] #datom[17592186045423 71 "foo" 13194139534318 true]], :tempids {-9223350046623220360 17592186045423}}
(d/entity (d/db conn) [:variant-context/id "foo"])
=> {:db/id 17592186045423}
@(d/transact conn [{:db/id (d/tempid :db.part/user) :sample/variant-contexts [:variant-context/id "foo"]}])
IllegalArgumentExceptionInfo :db.error/not-an-entity Unable to resolve entity: foo in datom [#db/id[:db.part/user -1000073] :sample/variant-contexts "foo"]  datomic.error/arg (error.clj:57)
@(d/transact conn [{:db/id (d/tempid :db.part/user) :sample/variant-contexts 17592186045423}])
=> {:db-before datomic.db.Db@9bbff236, :db-after datomic.db.Db@1acb01b2, :tx-data [#datom[13194139534320 50 #inst "2015-11-30T20:29:00.607-00:00" 13194139534320 true] #datom[17592186045425 70 17592186045423 13194139534320 true]], :tempids {-9223350046623220362 17592186045425}}

; now change cardinality on :sample/variant-contexts to one and repeat:

 {:db/index false,
  :db/valueType :db.type/ref,
  :db/noHistory false,
  :db/isComponent true,
  :db.install/_attribute :db.part/db,
  :db/fulltext false,
  :db/cardinality :db.cardinality/one,
  :db/doc "",
  :db/id {:part :db.part/db, :idx -1000057},
  :db/ident :sample/variant-contexts}

@(d/transact conn [{:db/id (d/tempid :db.part/user) :variant-context/id "foo"}])
=> {:db-before datomic.db.Db@88357062, :db-after datomic.db.Db@ac198ac, :tx-data [#datom[13194139534318 50 #inst "2015-11-30T20:59:36.522-00:00" 13194139534318 true] #datom[17592186045423 71 "foo" 13194139534318 true]], :tempids {-9223350046623220352 17592186045423}}
(d/entity (d/db conn) [:variant-context/id "foo"])
=> {:db/id 17592186045423}
@(d/transact conn [{:db/id (d/tempid :db.part/user) :sample/variant-contexts [:variant-context/id "foo"]}])
=> {:db-before datomic.db.Db@ac198ac, :db-after datomic.db.Db@b72bc00f, :tx-data [#datom[13194139534320 50 #inst "2015-11-30T20:59:50.938-00:00" 13194139534320 true] #datom[17592186045425 70 17592186045423 13194139534320 true]], :tempids {-9223350046623220353 17592186045425}}

; scenarios are identical except that in the first cardinality is many and in the second it's one!