avodonosov/datomic-helpers

Convenience functions to populate Datomic DB with data, to define DB schema.

datomic-helpers's Issues

How would I refer to non-nested (sibling) entities

Looking at the code I was first under the impression that perhaps you were relying on datomic's non-duplicate support for forcing entities that might be referenced in siblings (but should be a single entity) from being duplicated; however, it seems this is not the case. When I run your sample from the README and look at the database I see this:

 {:community/neighborhood {:db/id 17592186045445}, :community/type #{:community.type/email-list}, :community/orgtype :community.orgtype/community, :community/name "Alki News", :community/category #{"members of the Alki Community Council and residents of the Alki Beach neighborhood"}, :community/url "http://groups.yahoo.com/group/alkibeachcommunity/", :db/id 17592186045444}
 {:community/neighborhood {:db/id 17592186045448}, :community/type #{:community.type/blog}, :community/orgtype :community.orgtype/community, :community/name "Alki News/Alki Community Council", :community/category #{"news" "council meetings"}, :community/url "http://alkinews.wordpress.com/", :db/id 17592186045447}

and in these two entities you can see from the source that the neighborhood has the same name (and the implication in the original is that these should be collapsed into the same entity), but these sibling records end up generating two different entities for the same (:community/neighborhood -> Alki) neighborhood.

It seems that an internal memoization of maps by reference would allow you to do this:

;; pre-define a map (which will have a single reference)
(def common-thing { :neighborhood/name "Alki" })

then you could use the common-thing in multiple places within the data structure in the next to-transaction:

;; to-transaction remembers references it has generated IDs for, and re-uses the same 
;; tempid for repeated references.
(mapcat to-transaction [{:comminuty/neighborhood common-thing ... }
                        {:community/neighborhood common-thing ...}])

If this seems reasonable, I could look at making a patch and sending a pull request.