Question

I’m interested in storing multiple email addresses for an individual in a single mongo document e.g.:

{
 first_name: "Johnny"
 last_name: "Tester"
 emails: ["[e-mail]", "[e-mail]"]
}

Is it possible for me to ensure that when I attempt to push a value on to the emails array that it doesn’t already exist? If it does exist I want it to be added but if it doesn’t exist I don’t want it to be added. I’m trying to avoid making two queries (read then write) which would also make it unsafe for threaded environments. Thanks!

Answer 1

And I’ve since found the answer using $addToSet, found here: http://www.mongodb.org/display/DOCS/Updating#Updating-%24addToSetand%24each