upsert

verb

1. (transitive)To insert rows into a database table if they do not already exist, or update them if they do.

   “Each entity event is upserted into the key/value table, such that the most recently read event for a given key is represented.”

noun

1. An operation that inserts rows into a database table if they do not already exist, or updates them if they do.

   “The upsert option lets you specify whether the update should be an upsert—that is, it tells MongoDB to update the record if it exists, and create it if it doesn't.”