Clojurians Log v2

Hmmmm. No. It seems OK, which suggests a bug. I'll get onto that today

Thank you very much!

I am wondering whether it might be better to be more specific with the attribute filter and instead of saying "I want any of these attributes" say "for each of the entities, I want these attributes", i.e. something like:

'[:find ?e ?a ?v
         :where [?e ?a ?v]
         ;; TODO how to say that the output ?e is either of ?o, ?p ?
         [?o :order/product ?p] ; we are interested in an order and its product
         ;; Filter the attributes of order and product we want:
         (or [?o :order/descr ?v]
             [?p :product/name ?v])]

This is definitely an unexpected bug. The place where your error occurs can only be called when the node could not be "encapsulated" into a long value. But it's an internal node, and they can always be encapsulated into a long value. So I don't know how this code can ever be called!?! I'm trying to duplicate it here, but I'd love a stack trace

Oh good... I was able to duplicate it 🙂

OK. I found my problem. I tried to do something clever, and I did not realize that Clojure does something cleverer. Anyway, a fix will be in the next release. Meanwhile, the solution is to wrap the result in a map with the key :tx-data

i.e.

(defn retract-entity [db id]
  (d/transact
    db
    {:tx-data
      (d/q '[:find :db/retract ?e ?a ?v :where [?e ?a ?v] [?e :id ?id] :in $ ?id]
              db id)}))

If anyone is curious, it was caused by me being silly: https://twitter.com/quoll/status/1505316312821731331

Thanks a lot!

This will work, but I'd probably bind ?a instead of using a filter:

(d/q '[:find ?e ?a ?v
       :in $ [?a ...]
       :where [?e ?a ?v]
              (or [?e :order/product]
                  [_ :order/product ?e])]
      d [:order/descr :product/name])

Ah, thanks a lot!

Uh... thank you 🙂 I never know what I say on those things. I worry that I sound like an idiot! 🤣

Not at all. It was all very very interesting! 🙂

Seconded, that was interesting

Thank you! > I'm not quite sure of what you're trying to find here To explain: I am making an Asami adapter for the #fulcro Rapid Application Development library and thus, given an EDN Query Language (EQL) query such as [:order/id :order/descr {:order/product [:product/id :product/name]}] I need to return the corresponding data (in this case something like {:order/id 1, :order/descr "Buy ETH", :order/product {:product/id 101, :product/name "Ether"}} ). In Datomic it is achieved by a trivial translation of the EQL to a Datomic pull syntax. So I essentially need to implement something like Pull on top of Asami. My idea was to write a query that fetches all the relevant EAV triplets and (re)construct the desired data tree from that,