Hi, I’m looking for a way to manage ‘migrations’ with Datomic. I found https://github.com/rkneufeld/conformity by Ryan Kneufeld. Is this still a good way to go or do people have different/better strategies? Thanks in advance.

@juliobarros You might want to read http://blog.datomic.com/2017/01/the-ten-rules-of-schema-growth.html

@marshall yeah but I still need a way to manage growth. I didn’t necessarily mean changing or breaking the schema.

gotcha

@juliobarros I prefer a simple .clj file with migrations

I do that for SQL as well as for Datomic

migration frameworks are frequently overengineered

besides the Datomic schema is often idempotent

I suspect re-asserting the schema on each peer start would not be harmful

Thanks @pesterhazy … I haven’t kept up with Datomic lately but I thought I remembered the guideline to not reassert datoms (including schema). Anyway, conformity looks lightweight enough so I’ll go with that. Thanks again.

Hi, I’m trying to load some data into datomic. The entities I’m trying to load have a reference to entities already in the db. Do I have to look up those entity reference before hand, or is there a way to do it all in one go.

Existing: {:db/id 1234 :location “New York”} New {:name “John” :location <entity ref>}

Can you do this {:name “John” :location [:find e? :where [e? :location “New York]]}

@brett http://blog.datomic.com/2014/02/datomic-lookup-refs.html

you’ll need a unique attribute on the ‘target'

i.e. if your location entity has a :location/name attribute that is db.unique/identity

you could use [:location/name “New York”]

instead of having to look up the entity ID

ok, I was looking at that, but thought it was only for updating same entity. Let me give that a try. thx.

^this would be the preferred approach in fact - generally you should avoid using entity IDs directly