Add an upsert method

I think you’ll be interested in this ticket/project, specifically

Hmm - I don’t know why this comment would be in the docs:

SQL Server requires a second argument with the column(s) that uniquely identify records:

Maybe that allows on-the-fly duplicate avoidance, but if you use an index with IGNORE_DUP_KEY, you don’t need to change anything about your regular queries.