Datomic attribute schema fn with sane defaults.

gistfile1.clj

(ns foo.schema
  (:require [datomic.api :refer [tempid]]))

;; Datomic schema is wordy, so apply some sane defaults and allow overriding where needed.

(defn- attribute [ident & options]
  (let [defaults {:db/id (tempid :db.part/db)
                  :db/ident ident
                  :db/valueType :db.type/string
                  :db/cardinality :db.cardinality/one
                  :db.install/_attribute :db.part/db}]
    (merge defaults
           (apply hash-map options))))

;; The minimum you can provide is just an attribute name...

(attribute :user/name)

;; Then you can customize other attributes as required, for
;; example setting a custom data type...

(attribute :user/age
           :db/valueType :db.type/long)

;; And all other attributes as well of course...

(attribute :user/friends
           :db/valueType :db.type/ref
           :db/cardinality :db.cardinality/many)