在MongoDB中插入或更新多个文档

Question

I want to implement hashtags functionality with NodeJS and MongoDB support, so that I can also count the uses. Whenever a user adds hashtags to a page, I want to push or update them in the database. Each hastag looks like this:

{_id:<auto>, name:'hashtag_name', uses: 0}

The problem I'm facing is that the user can add new tags as well, so when he clicks 'done', I have to increment the 'uses' field for the existing tags, and add the new ones. The trick is how to do this with only one Mongo instruction? So far I thought of 2 possible ways of achieving this, but I'm not particularly happy with either:

Option 1

I have a service which fetches the existing tags from the db before the user starts to write a new article. Based on this, I can detect which tags are new, and run 2 queries: one which will add the new tags, and another which will update the existing one

Option 2

I will send the list of tags to the server, and there I will run a find() for every tag; if I found one, I'll update, if not, I'll create it.

Option 3 (without solution for now)

Best option would be to run a query which takes an array of tag names, do a $inc operation for the existing ones, and add the missing ones.

The question

Is there a better solution? Can I achieve the end result from option #3?

Answer 1

You should do something like this, all of them will be executed in one batch, this is only an snippet idea how to do it:

var db = new Db('DBName', new Server('localhost', 27017));
    // Establish connection to db
    db.open(function(err, db) {
    // Get the collection
    var col = db.collection('myCollection');

    var batch = col.initializeUnorderedBulkOp();

    for (var tag in hashTagList){
      // Add all tags to be executed (inserted or updated) 
      batch.find({_id:tag.id}).upsert().updateOne({$inc: {uses:1}});
    }

    batch.execute(function(err, result) {
      db.close();
    });
  });

Answer 2

I would use the Bulk method offered by Mongodb since version 2.6. In the same you could perform insertion operations when the tag is new and the counter update when it already exists.