there is two problem confuse me about Datomic: 1. Should I prefer enumerated value than keyword. db.type/ref OR db.type/keyword 2. I have an entity (a user) which created old thant t. Is this user will recycle when I call (gc-storage conn t) if this user never updated after created?

Hi @isaac - see my reply here: https://groups.google.com/d/msg/datomic/m2aVI9IY9Ms/o7CI0AnMAAAJ

@bkamphaus: there is no reply

@isaac: there definitely is one, but Google Groups always had bad delays for update/refresh - it may take a couple of minutes to show up in your view. File under “eventually consistent” I guess.

@bkamphaus: I seen your reply. thanks

I’m trying to parameterize the arguments to a find specification

(defn sample-n [db n]
  (d/q '[:find (sample ?n ?a) .
         :in $ ?n
         :where [?a :account/uuid]]
       db n))

but I’m getting an Exception: clojure.lang.Symbol cannot be cast to java.lang.Number

what’s the right way to pass in n?

you could stick the number in the quoted form, which is how I've seen it done in the examples

`[:find (sample ~n ?a) ...]

but my experience with datomic is limited, so I am not sure if you'll run in to issues using syntax-quote there

like this?

(defn sample-n [db n]
  (d/q `[:find (sample ~n ?a) .
         :in $
         :where [?a :account/uuid]]
       db))

yeah

are you sure you want the find scalar dot?

That results in :db.error/invalid-data-source Nil or missing data source. Did you forget to pass a database argument? when called

I don't think that makes sense with sample

which is surprising for me

without the dot it returns the sample with another layer of nesting

oh, no kidding

you could try building the expression using regular quote, in case the namespace qualifying that syntax quote does is screwing it up

[:find (list 'sample n '?a) '. :in '$ :where ['?a :account/uuid]]

interesting thing is, this seems to work in pull expressions:

(defn all-products [db]
  (d/q '[:find [(pull ?e product-props) ...]
         :in $ product-props
         :where [?e :product/slug]]
       db product-props))

not sure what’s different about the two

you used ?n for the other one

not n

@wei: This might be what you’re shooting for:

(defn sample-query [x]
  (let [my-sample (list 'sample x '?m)]
    {:find [my-sample]
     :in '[$]
     :where '[[?m :track/name]]}))


(d/q (sample-query 3) db)