Example in README not working

[devth]

I pasted the example from the README in my REPL but ran into this exception as soon as I try to use any of the fns created by (dc/create-model-fns model-namespace):

ClassCastException clojure.lang.Var$Unbound cannot be cast to datomic.Connection  datomic.api/transact (api.clj:64)

Using this variant to create the db:

(ns server)
(require '[datomico.core :as dc])
(dc/start {:uri "datomic:mem://my-app"
           :schemas [models.user/schema]})

If I instead use this variant, it works:

(ns user)
(require '[datomico.core :as dc])
(dc/start {:dynamic-vars true
           :schemas [models.user/schema]})

I'm running into the same exception in my actual code as well, trying to connect to a datomic-free transactor. Looks like dc/start with :dynamic-vars properly returns a datomico.db/entity while specifying a :uri returns nil.

Using the 0.1.0 release.

Edit: It looks like I'm missing something fundamental about how to set the dynamic *db* value. Apparently :dynamic-vars true does this for you but is "Not recommended for application code. Default is false." What is the correct way to set *db* and why wouldn't you always want it to be the most recent db version by default?

[cldwalker]

Hey. Sorry for the delay. The first variant is not meant to be used from a repl and requires explicit handling of connection and db. It assumes it's a web app and that you would be wrapping your middleware with wrap-datomic. I'll update the docs to be more clear.

To answer your question about, why you don't want to do this by default requires looking into what happens when you use :dynamic-vars. On every query, it creates a new db object to be passed to datomic. While this is a nice convenience, you should be using wrap-datomic or something that explicitly handles updating db and connection as needed.

[devth]

Got it, thanks.