Upserting in Mongo DB using official C# driver

Question

In the official documentation of mongodb they mention upserts, so it would be really nice to write an upsert command instead of:

if (_campaignRepo.Exists(cam         


        

Answer 1

Starting from v2.0 of the driver there's a new async-only API. The old API should no longer be used as it's a blocking facade over the new API and is deprecated.

The currently recommended way to upsert a document is by calling and awaiting ReplaceOneAsync with the IsUpsert flag turned on and a filter that matches the relevant document:

Hamster hamster = ...
var replaceOneResult = await collection.ReplaceOneAsync(
    doc => doc.Id == hamster.Id, 
    hamster, 
    new UpdateOptions {IsUpsert = true});

You can check whether the operation was an insert or an update by looking at ReplaceOneResult.MatchedCount: