将多个文档上传到mongoDB

Question

I have a array of values, some of the values in the array may already be present in my database. I want to upsert the new values and increase the count of the old values. One way to do this is :

• For all the values that are present in the database use a update command and increment count. It can be done using : db.test.update({ link: {$in: ["A", "B"]}}, {$inc: {count: 1}}, {upsert: true, multi:true})

• For all the values not present in my database, check each and every value and upsert it into the database.

The second step may put some load on the network. Is there any way to do the second step in one command?

For example consider this :

Initial state of my database :

{ "_id" : ObjectId("5a45f97f84527190e1f28cb7"), "link" : "A", "count" : 3 } 

and I have the array as following: const values = ['A', 'B', 'C']

Now I want to have something like this:

{"_id": ObjectId("abc"), "link": "A", "count" : 4},
{"_id": ObjectId("xyz"), "link": "B", "count" : 1},
{"_id": ObjectId("fgh"), "link": "C", "count" : 1}

Answer 1

To achieve the second step (as you mentioned) optimally you can perform lookup in your DB using find() method.

If the array value isn't present in the DB , then find() is gonna return an empty object. So you just see the length of the object returned from find() . If found empty, insert into DB else update the info.

Example code for nodejs environment:

var db = mongojs('dbname', ['collection_name']);

var theLink = 'XYZ';

db.collection_name.find({link: theLink}, function (err, obj) {
    if (err)
        throw err;
    if (obj.length == 0)
        // write logic to insert
    else
        // write logic to update
});