It seems like I can look up attributes in an as-of database before they are created - is this expected behavior?

(d/create-database "datomic:")
(def conn (d/connect "datomic:"))

(d/transact conn [{:db/ident :my/attr
                   :db/valueType :db.type/string
                   :db/cardinality :db.cardinality/one}])

(def db (d/db conn))
(def then (java.util.Date.))

(d/transact conn [{:db/ident :my/attr-2
                   :db/valueType :db.type/string
                   :db/cardinality :db.cardinality/one}])

;; 1. Look up in the old db
(d/entity db :my/attr-2) ;;=> nil

;; 2. Look up in an equivalent as-of db
(d/entity (d/as-of (d/db conn) then) :my/attr-2) ;;=> {:db/id 74}