Datomic schema

description.txt

A profile handle needs to be unique, but the profile can be "owned" by either a person or a group.

schema1 makes it hard (impossible?) to validate with clojure.spec.

schema2 it would be possible to validate with a or in clojure.spec, but would have the drawback of not knowing by just looking at the profile` if it is owned by a group or a person.

Questions:

1) Which one is more idiomatic?
2) Is "this would be easier to validated with clojure.spec" a valid argument for datomic schema design
3) What to we gain though the profile entity indirection? :profile/handle could be an attribute on the person or group entity directly
4) When using the second approach, should we add an :profile/owner-type attribute which defines what :profile/owner references?
5) Should we consider isComponent for this?

schema1.clj

;; 
(def profile
  [{:db/ident :profile/handle
    :db/unique :db.unique/value
    :db/valueType :db.type/string
    :db/cardinality :db.cardinality/one}

   {:db/ident :profile/website
    :db/valueType :db.type/string
    :db/cardinality :db.cardinality/one}])

(def person
  [{:db/ident :person/email
    :db/unique :db.unique/value
    :db/valueType :db.type/string
    :db/cardinality :db.cardinality/one}

   {:db/ident :person/password-digest
    :db/valueType :db.type/string
    :db/cardinality :db.cardinality/one
    :db/doc "bcrypt encoded"}

   {:db/ident :person/profile
    :db/valueType :db.type/ref
    :db/cardinality :db.cardinality/one}])

(def group
  [{:db/ident :group/name
    :db/valueType :db.type/string
    :db/cardinality :db.cardinality/one}

   {:db/ident :group/profile
    :db/valueType :db.type/ref
    :db/cardinality :db.cardinality/one}

   {:db/ident :group/member
    :db/valueType :db.type/ref
    :db/cardinality :db.cardinality/many}])

schema2.clj

(def profile
  [{:db/ident :profile/handle
    :db/unique :db.unique/value
    :db/valueType :db.type/string
    :db/cardinality :db.cardinality/one}

   {:db/ident :profile/website
    :db/valueType :db.type/string
    :db/cardinality :db.cardinality/one}

   {:db/ident :profile/owner
    :db/valueType :db.type/ref
    :db/cardinality :db.cardinality/one}])

(def person
  [{:db/ident :person/email
    :db/unique :db.unique/value
    :db/valueType :db.type/string
    :db/cardinality :db.cardinality/one}

   {:db/ident :person/password-digest
    :db/valueType :db.type/string
    :db/cardinality :db.cardinality/one
    :db/doc "bcrypt encoded"}])

(def group
  [{:db/ident :group/name
    :db/valueType :db.type/string
    :db/cardinality :db.cardinality/one}

   {:db/ident :group/member
    :db/valueType :db.type/ref
    :db/cardinality :db.cardinality/many}])