Insert Into Array of object MongoDB

Question

I have

{
    "_id" : ObjectId("5a25af80d2c4dd065991dccc"),
    "username" : "[email protected]",
    "password" : "$2a$10$ptFyLKtyyrL5gMYdXS6wV.HLUA4Py5iudMJDldf5qsHFS4.9TPCyy",
    "role" : "Admin",
    "__v" : 0,
    "list" : [ 
        {
            "name" : "We",
            "arr" : [ 
                "5a26d554677475818a795f75", 
                "5a395bb0976d5304c07f7dd4"
            ]
        }, 
        {
            "name" : "sandeep",
            "arr" : [ 
                "5a26d554677475818a795f75"
            ]
        }
    ]
}

I want to add an element inside list.arr where name = 'we' and add only if the element does not exist

how do i perform this query.

you can't achieve this one with single query, because this is nested document array. — Dimuthu
– Dimuthu, Commented Dec 25, 2017 at 2:09

0.sh · Accepted Answer · 2017-12-25 08:51:27Z

1

if i properly understood you question,you want to match name field with we key,and update arr only if it exists ?, you have to use elemMatch, in other to get the right document

db.test.update({ list: { $elemMatch: { name: "We" , arr: { $nin: [ "valuette" ] }} } }, {  $push: { "list.$.arr": "valuette" } } );

the $ in "list.$.arr" matches the specified index that matches name field with we value

update: to answer OP question

edited Dec 25, 2017 at 8:51

answered Dec 25, 2017 at 2:49

0.sh

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3 Comments

Sandeep Ranjan Over a year ago

It is if the element inside the array exist

Sandeep Ranjan Over a year ago

I want to push if the element does not exist inside the array

0.sh Over a year ago

ok, check the new update, it solves your problem, $nin operator checks if valuette is not in the arr array, then it does the update

Insane noise · Accepted Answer · 2017-12-25 08:54:46Z

Intial database structure

> db.collection.find().pretty()
{
    "_id" : ObjectId("5a25af80d2c4dd065991dccc"),
    "username" : "[email protected]",
    "password" : "$2a$10$ptFyLKtyyrL5gMYdXS6wV.HLUA4Py5iudMJDldf5qsHFS4.9TPCyy",
    "role" : "Admin",
    "__v" : 0,
    "list" : [
        {
            "name" : "We",
            "arr" : [
                "5a26d554677475818a795f75",
                "5a395bb0976d5304c07f7dd4"
            ]
        },
        {
            "name" : "sandeep",
            "arr" : [
                "5a26d554677475818a795f75"
            ]
        }
    ]
}

Query executed

> db.collection.update({ list: { $elemMatch: { name: "We" , arr: {$nin: ["55555555555555555"]} } } }, {  $push: { "list.$.arr": "55555555555555555" } } )
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

New database structure

> db.collection.find().pretty()
{
    "_id" : ObjectId("5a25af80d2c4dd065991dccc"),
    "username" : "[email protected]",
    "password" : "$2a$10$ptFyLKtyyrL5gMYdXS6wV.HLUA4Py5iudMJDldf5qsHFS4.9TPCyy",
    "role" : "Admin",
    "__v" : 0,
    "list" : [
        {
            "name" : "We",
            "arr" : [
                "5a26d554677475818a795f75",
                "5a395bb0976d5304c07f7dd4",
                "55555555555555555"
            ]
        },
        {
            "name" : "sandeep",
            "arr" : [
                "5a26d554677475818a795f75"
            ]
        }
    ]
}

Again same query Executed

> db.collection.update({ list: { $elemMatch: { name: "We" , arr: {$nin: ["55555555555555555"]} } } }, {  $push: { "list.$.arr": "55555555555555555" } } )
WriteResult({ "nMatched" : 0, "nUpserted" : 0, "nModified" : 0 })

Checking the database structure again

> db.collection.find().pretty()
{
    "_id" : ObjectId("5a25af80d2c4dd065991dccc"),
    "username" : "[email protected]",
    "password" : "$2a$10$ptFyLKtyyrL5gMYdXS6wV.HLUA4Py5iudMJDldf5qsHFS4.9TPCyy",
    "role" : "Admin",
    "__v" : 0,
    "list" : [
        {
            "name" : "We",
            "arr" : [
                "5a26d554677475818a795f75",
                "5a395bb0976d5304c07f7dd4",
                "55555555555555555"
            ]
        },
        {
            "name" : "sandeep",
            "arr" : [
                "5a26d554677475818a795f75"
            ]
        }
    ]
}

No changes Found

@SandeepRanjan ill check it again and will update the above asap

Sandeep Ranjan · Accepted Answer · 2017-12-25 08:26:15Z

0

By using this nested query I solved this problem. I'm doing it with Node JS

router.post('/prevList', (req, res) => {
  User.update({'_id':req.user.id, list: { $elemMatch: { name: req.body.name } } },{  $addToSet: { "list.$.arr": {$each: req.body.arr} } },function(err,data) {
    console.log(data);
    res.send(data)
  });
});

Here

req.body: {name:'we',arr:["5a395bb0976d5304c07f7dd4"]}

and req.user.id is the auth id.

Hope this helps you all too.

answered Dec 25, 2017 at 8:26

Sandeep Ranjan

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