Clojurians Log v2

What's the case where you're not sure if you should add a new uuid though? It sounds like you either have it provided from your data source, or you should add one.

It's that I'm sometimes not so clear in my code to build transactions whether this is an update or a new value.

I ended up putting in the necessary conditions by hand. I'm not thrilled about that, but there's not really a good alternative, and the set of functions adding and updating things is limited.

If you make the uuid unique on the schema, the entity will be up setter

Upsertted

So you can just transact your nested objects with uids in them directly: if the entity exists it will be a upsert, if it doesn't exist it will be an insert

(require '[datascript.core :as d])
;; :db/ident is already unique
(def schema {:children {:db/cardinality :db.cardinality/many
                        :db/valueType   :db.type/ref}})
(def conn (d/create-conn schema))

(d/transact! conn [{:db/ident "uuid1"
                    :prop1 1}])
(d/touch (d/entity @conn [:db/ident "uuid1"]))
;; => {:prop1 1, :db/ident "uuid1", :db/id 1}

(d/transact! conn [{:db/ident "uuid1"
                    :prop2 2}])
(d/touch (d/entity @conn [:db/ident "uuid1"]))
;; => {:prop1 1, :prop2 2, :db/ident "uuid1", :db/id 1}


(d/transact! conn [{:db/ident "uuid1"
                    :children [{:db/ident "uuid2"
                                :prop1 1}
                               {:db/ident "uuid3"
                                :prop2 2}]}])
(d/touch (d/entity @conn [:db/ident "uuid1"]))
;; => {:children #{#:db{:id 2} #:db{:id 3}}, :prop1 1, :prop2 2, :db/ident "uuid1", :db/id 1}

(d/touch (d/entity @conn [:db/ident "uuid2"]))
;; => {:prop1 1, :db/ident "uuid2", :db/id 2}

(d/touch (d/entity @conn [:db/ident "uuid3"]))
;; => {:prop2 2, :db/ident "uuid3", :db/id 3}

I used to do this with a custom :block/uid prop but I've since learned that :db/ident seems to already be unique

you can also query directly for the unique prop with the ref lookup [:db/ident "whatever"] on pull/entity/etc

yes, I'm familiar with that approach. it's working well, I was just wondering if there was a slick way to hook in to attach a UUID to every entity, or nearly every entity. it's working fine, so no worries now.

You can totally store uuids, either as strings or as uuid type, just store them as an attributte

is there a slicker way to enforce them than editing all the code that inserts new entities, and adding a post-test fixture that checks for anything without one?

no, I don’t think so

fair enough. thanks!

ive definitely had this need and i think niki talked about using uuids in a hypothetical datascript 2 https://tonsky.me/blog/datascript-2/

but yeah i just added them manually in all my transaction fns