DB.UpdateAndGet() + "Insert an entity if it doesn't exist"

[pachanga]

Hi!

I was wondering whether it's possible to update and get an entity or insert and retrieve it using one API call, so that it happens atomically on Mongo level?

Something as follows:

var book = await DB.UpdateAndGet<Book>()
    .Match(b => b.ID == "xxxxxxxxxxxxx")
    .Modify(b => b.Title, "updated title")
    .ModifyOnInsert(b  => b.Author, "Bob") // this part is executed only if entity doesn't exist and it's inserted
     .ModifyOnInsert(b  => b.Links, 1) // this part is executed only if entity doesn't exist and it's inserted
    .ExecuteAsync(); 

[dj-nitehawk]

you can do an upsert as shown here: https://github.com/dj-nitehawk/MongoDB.Entities/issues/216#issuecomment-1868503265 but i don't think the mongo driver can do different things depending on whether its an update or insert. i.e. if you upsert, the document/entity will have both author set to bob & links set to 1 in both cases.