How to increment existing value in MongoDB

Question

I am using Stitch platform by MongoDB. I want to store a value and a count associated with that value in the database. Now the value m

Answer 1

According to MongoDb 3.6:

db.collection.update(query, update, options)

Modifies an existing document or documents in a collection. The method can modify specific fields of an existing document or documents or replace an existing document entirely, depending on the update parameter.

The meaning is that you can upsert multiple documents using update.

First you should create array from your map that contains only the value.

const arrayOfValues = ['value_01', 'values_02'];

Then you should use the upsert + multi options on the update method:

db.foo.update({value: { $in: arrayOfValues}}, {$inc: {count:1}}, { upsert: true, multi: true });

Test output:

> db.createCollection("test");
{ "ok" : 1 }
> db.test.insertMany([{value: "a"}, {value: "b"}, {value: "c"}];
... );
2017-12-31T12:12:18.040+0200 E QUERY    [thread1] SyntaxError: missing ) after argument list @(shell):1:61
> db.test.insertMany([{value: "a"}, {value: "b"}, {value: "c"}]);
{
    "acknowledged" : true,
    "insertedIds" : [
        ObjectId("5a48b8061b98cc5ac252e435"),
        ObjectId("5a48b8061b98cc5ac252e436"),
        ObjectId("5a48b8061b98cc5ac252e437")
    ]
}
> db.test.find();
{ "_id" : ObjectId("5a48b8061b98cc5ac252e435"), "value" : "a" }
{ "_id" : ObjectId("5a48b8061b98cc5ac252e436"), "value" : "b" }
{ "_id" : ObjectId("5a48b8061b98cc5ac252e437"), "value" : "c" }
> db.test.update({value: { $in: ["a", "b", "c"]}}, {$inc: {count:1}}, { upsert: true, multi: true });
WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 3 })
> db.test.find();
{ "_id" : ObjectId("5a48b8061b98cc5ac252e435"), "value" : "a", "count" : 1 }
{ "_id" : ObjectId("5a48b8061b98cc5ac252e436"), "value" : "b", "count" : 1 }
{ "_id" : ObjectId("5a48b8061b98cc5ac252e437"), "value" : "c", "count" : 1 }
> db.test.update({value: { $in: ["a", "b", "c"]}}, {$inc: {count:1}}, { upsert: true, multi: true });
WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 3 })
> db.test.find();
{ "_id" : ObjectId("5a48b8061b98cc5ac252e435"), "value" : "a", "count" : 2 }
{ "_id" : ObjectId("5a48b8061b98cc5ac252e436"), "value" : "b", "count" : 2 }
{ "_id" : ObjectId("5a48b8061b98cc5ac252e437"), "value" : "c", "count" : 2 }
> db.test.update({value: { $in: ["a", "b", "c"]}}, {$inc: {count:1}}, { upsert: true, multi: true });
WriteResult({ "nMatched" : 3, "nUpserted" : 0, "nModified" : 3 })

Hope it was helpful :)