How to update multiple mongodb documents with different values based on a key?

Question

I am trying to figure out a way to update multiple documents in a collection with different values based on a key.

persons collection:

 {
  _id: 1,
  name: "Jackie Chan",
  Country: Australia
},
{
  _id: 2,
  name: "Brad Pitt",
  Country: Russia
},
{
  _id: 3,
  name: "Al Pacino",
  Country: USA
}

Payload:

{
 _id: 1,
 name:"Jackie Chan",
 Country:"China"
}
,{
 _id: 2,
 name:"Brad Pitt",
 Country:"USA"
}

persons collection after update:

{
      _id: 1,
      name: "Jackie Chan",
      Country: "China"
    },
    {
      _id: 2,
      name: "Brad Pitt",
      Country: "USA"
    },
    {
      _id: 3,
      name: "Al Pacino",
      Country: "USA"
    }

SQL equivalent would be :

update t1.country = t2.country from persons t1 inner join #temptable t2 on t1._id=t2._id

None of the examples mentioned here explain how to do it. Unless I am missing something?

Sort of yes. If you mean sending multiple documents to db for update at once then yes. @Joe — SamuraiJack
– SamuraiJack, Commented Aug 28, 2020 at 9:10
I'm not really sure how Brat Pitt/Russia + Brad Pitt/USA = Brad Pitt/China. — Joe
– Joe, Commented Aug 28, 2020 at 9:14
does this help: docs.mongodb.com/manual/core/bulk-write-operations/… — Joe
– Joe, Commented Aug 28, 2020 at 9:14
@Joe that was a mistake on my part while copy pasting. I have corrected it. According to the link that you have shared.. does it mean I will have to have multiple { updateOne :{}} within bulkWrite() . As many times as there are records to be updated ? — SamuraiJack
– SamuraiJack, Commented Aug 28, 2020 at 9:20

Joe · Accepted Answer · 2020-08-28 09:36:17Z

1

It seems like bulk write is exactly the right tool. Simply map the payload array so to make it an array of updates, such as:

db.persons.bulkWrite(payload.map( function(p) { 
      return { updateOne:{
                    filter: {_id: p._id},
                    update: {$set: {Country: p.Country}}
      }}
}))

answered Aug 28, 2020 at 9:36

Joe

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5 Comments

SamuraiJack Over a year ago

I am not able to get this to work with ObjectId, any ideas?

await this.db.collection("persons").bulkWrite([{ _id: { "$toObjectId": "5f3258cfbaaccedaa5dd2d96" }, phone: "123456" }         , { _id: { "$toObjectId": "5f3258cfbaaccedaa5dd2da2" }, phone: "1234567" }].map(function (p) {           return {             updateOne: {               filter: { _id: p._id },               update: { $set: { phone: p.phone } }             }           }         }))

SamuraiJack Over a year ago

ah got it.. i used new mongo.ObjectID("5f3258cfbaaccedaa5dd2da2") and it worked

SamuraiJack Over a year ago

I have a question though. I got this in response:

{ 	"acknowledged" : true, 	"deletedCount" : 0, 	"insertedCount" : 0, 	"matchedCount" : 2, 	"upsertedCount" : 0, 	"insertedIds" : { 		 	}, 	"upsertedIds" : { 		 	} }

Why is it that it says that 0 records were modified?

Joe Over a year ago

The existing document already had the value that the update operation was trying to set.

SamuraiJack Over a year ago

what happens if one insert fails?

Mallik · Accepted Answer · 2020-08-28 21:00:50Z

//code when run from mongodb client
> db.persons.find();
{ "_id" : 1, "name" : "Jackie Chan", "Country" : "China1" }
{ "_id" : 2, "name" : "Brad Pitt", "Country" : "Russia1" }
{ "_id" : 3, "name" : "Al Pacino", "Country" : "USA1" }
> var payload=[{_id: 1,name:"Jackie Chan",Country:"China2"},
...              {_id: 2,name: "Brad Pitt",Country: "Russia2"},
...              {_id: 3, name: "Al Pacino",Country: "USA2"}];
> print("payload: ",payload);
payload:  [object Object],[object Object],[object Object]
>
> db.persons.bulkWrite(payload.map( function(p) {
...       return { updateOne:{
...                     filter: {_id: p._id},
...                     update: {$set: {Country: p.Country}}
...       }}
... }));
{
        "acknowledged" : true,
        "deletedCount" : 0,
        "insertedCount" : 0,
        "matchedCount" : 3,
        "upsertedCount" : 0,
        "insertedIds" : {

        },
        "upsertedIds" : {

        }
}
> db.persons.find();
{ "_id" : 1, "name" : "Jackie Chan", "Country" : "China2" }
{ "_id" : 2, "name" : "Brad Pitt", "Country" : "Russia2" }
{ "_id" : 3, "name" : "Al Pacino", "Country" : "USA2" }
>

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