datomic 2017-04-12

Datomic transact-async use pipeline throws java.util.ConcurrentModificationException

How to do a 'group by'-like query? Having a dataset like:

1   yes
2   no
3   no
4   yes
...
I'd like to count how many times there's a yes and a no, so resulting in:
[["yes" 23]
 ["no" 19]]

Hey folks, I have a colleague who's really stuck on Java setup of Datomic. If it were Clojure, I could help and/or point him here, but I have zero idea where folks go for help with Java Datomic. Can anyone clue me in on that?

He's got it installed; he's just having problems with setup in his Java project.

I’m thinking of serializing entitymaps as an id and a t-value to store in some external system (e.g. Redis). has anyone taken this approach, or have already written an EDN tag-reader?

Alex Miller (Clojure team) 2017-04-12T18:20:05.924200Z

@eggsyntax the mailing list would probably be good https://groups.google.com/forum/#!forum/datomic

Thanks Alex 🙂

I’m trying to specify a time for a transaction as described here: http://docs.datomic.com/best-practices.html#set-txinstant-on-imports Does anyone see what I’m doing wrong here?

@(d/transact conn [{:db/id (d/tempid :db.part/user) :ti.location/name "somewhere"} {:db/id "datomic.tx" :db/txInstant #inst "2017-04-12T20:26Z"}])
datomic.impl.Exceptions$IllegalArgumentExceptionInfo: :db.error/not-an-entity Unable to resolve entity: datomic.tx in datom ["datomic.tx" :db/txInstant #inst "2017-04-12T20:26:00.000-00:00"]

@bmaddy what version of datomic?

@favila My project.clj has this: com.datomic/datomic-pro "0.9.5359"I’m trying to figure out what the db version is…

@bmaddy string tempids were not introduced until 0.9.5530

you can use the old method: {:db/id (d/tempid :db.part/tx) :db/txInstant #inst"..."}

Yep, that did it. Thanks @favila!