MongoDB: Update nested array element or insert it if not existing

Question

This is how a document structure could be in my case:

{
    "_id" : "P9H59RuSbnm45erj7",
    "description" : [
        {
            "content" : "Something",
            "language" : "en",
            "timestamp" : 1476958705
        },
        {
            "content" : "Irgendetwas",
            "language" : "de",
            "timestamp" : 1476958705
        }
    ]
}

Now I want to update the content of a specific language. But the description array could have missing languages.

{
    "_id" : "P9H59RuSbnm45erj7",
    "description" : [
        {
            "content" : "Something",
            "language" : "en",
            "timestamp" : 1476958705
        }
    ]
}

So what I am doing is to check first if the language is existing, then

If it is existing, I will do a simple update / $set
If it is not existing, I will do a update / $addToSet

My question is, if this can be simplified. Do I really have to check for the existing language and then use two different update-queries? With this the code gets pumped up...

I'm using this code in my meteor app, so I'm using minimongo.

if (Collection.find({ _id: 'P9H59RuSbnm45erj7', 'description.language': 'en' }).count() > 0) {
    Collection.update(
        {
            _id                   : 'P9H59RuSbnm45erj7',
            'description.language': 'en'
        },
        {
            $set: {
                'description.$.content'  : value,
                'description.$.timestamp': Math.floor(Date.now() / 1000)
            }
        }
    );
}
else {
    Collection.update(
        { _id: 'P9H59RuSbnm45erj7' },
        {
            $addToSet: {
                description: {
                    content  : value,
                    language : 'en',
                    timestamp: Math.floor(Date.now() / 1000)
                }
            }
        }
    );
}

Daniele Tassone · Accepted Answer · 2016-10-20 18:57:08Z

1

db.Test8.update(
      { _id: 1, "description.language":{$eq:"en"} },
      {
                $set: { "description.$.content": "content5" }
      },
      {}, function (err, result) {

          // if result.nMatched == 0 then make your $addToSet
          // because there are no query

       }
    );

The benefit to have the query in this was is to make most of the time 1-query instead of 2. And only rarely time 2-query.

Depending from your most frequently scenario. As you say most of the time is an update, then you can make 1query instead of 2 query.

I don't know any other way to make it better.

edited Oct 20, 2016 at 18:57

answered Oct 20, 2016 at 14:14

Daniele Tassone

2,1942 gold badges18 silver badges26 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user3142695 Over a year ago

I think in my case most of the time it is an update and rarely an push

Daniele Tassone Over a year ago

@user3142695 I will invert the query2 with query1.

Collectives™ on Stack Overflow

MongoDB: Update nested array element or insert it if not existing

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related