are there any idiomatic ways to represent an ordered list in datomic? more specifically, a queue

either by adding a "position" attribute, or by using a linked list

@pesterhazy linked list? like here? http://jmhofer.johoop.de/datomic/2012/08/18/linked-lists-in-datomic.html

[{:db/id #db/id[:db.part/db], :db/ident :content/name, ...
 {:db/id #db/id[:db.part/db], :db/ident :linkedList/head, ...
 {:db/id #db/id[:db.part/db], :db/ident :linkedList/tail, ...

there’s also this, evaluating it now https://github.com/dwhjames/datomic-linklist

https://github.com/dwhjames/datomic-linklist/blob/master/doc/api.md

I keep indexes in a list in a separate attribute.

{:x/ys #{1 2 3}
 :x/ys-order #{{:o/id 1 :o/idx 0}
               {:o/id 2 :o/idx 2}
               {:o/id 3 :o/idx 1}}}

(ys in my case are not components of x, and can have multiple "parent" collections)

only annoying thing is popping off the queue requires reshuffling all idxs

you can just grow idxs and pop the lowest one

but for queues linked list might be more suitable. I need to be able to swap/shuffle elements, so this :x/ys-order works for me

makes sense

it also helps with recursive pull patterns, if you happen to have parent/child of the same "type".

previously I had a wrapper object instead, so it looked like :x -> :w -> :y

pull patterns and queries were nightmare unpleasant

that’s a good consideration. wrappers do make queries more annoying

also thought about serializing to EDN a vector of uuids. makes some things easier, but then it’s not queryable

true, + extra special step

also storing blobs is not efficient in Datomic

once they're getting a bit bigger