Question

I’m having problems updating a record. My document structure is something like this:

"_id" : "1141825507009",
    "person" : [
        {
            "amount" : 25,
            "id" : "1141825507009"
        }
]

I want to increment person.amount by 3 where person.id is 1141825507009. That easy.
What about:

Increment person.amount  by 3 if person.id exist.
Add to person list with amount 3 and id 239something845 if person.id does not exist in list. 

Answer 1

I think what you want is https://jira.mongodb.org/browse/SERVER-340. You might want to watch/vote for.

If you don’t need to do it atomically, you could do something like:

db.foo.update({"person.id" : {$exists : false}, /* other criteria */}, 
    {$inc : {"person.amount":3}});
var result = db.runCommand({getLastError:1})
if (result.n == 0) { // nothing updated, person.id must exist
    db.foo.update({/* criteria */}, 
        {$addToSet : {person : {amount:3, id:"239something845"}}});
}