Match query for json object mongodb data returning empty array

MongoDB Atlas
,
1

I’m building REST APIs in node.js using express.js library. For the embedded data stored in mongodb as json object, I’m trying to get specific data by filtering, thereby using the aggregate match to achieve so.

For the users collection, I’ve the data as below



[
{
  unique_key:"1",
  user_form:
  {  
    user_details:
    {  
      first_name:"Tely",
      last_name:"Zed"
    }
  }
},
{
  unique_key:"2",
  user_form:
  {  
    user_details:
    {  
      first_name:"Rock",
      last_name:"Monty"
    }
  }
}
]

I want to get data of user by searching name. So I’m using aggregate method and then using match operator to achieve it. User is the name of the model. For filtering I’m using below aggregate method on User model.

User.aggregate([
  {
    $match: {
      user_form:
      {
        user_details:
        {
          first_name: req.body.user_form.user_details.first_name
        }
      }
    }
  }
  
])
.exec(function(err,filteredUsers){  
  if(filteredUsers) {
    console.log(filteredUsers);
    res.json({
      "msg": "Successfully gets the filtered users",
      "data": filteredUsers,
      "success": true
    });
  } if(err){
    res.json({
      "msg":"Error occured while filtering users",
      "error": err ,
      "success":false
    });
  }
})

Now when I’m posting request from postman with searching with first_name as Rock in postman //body as shown below.

{
 user_form:
 {  
  user_details:
  {  
   first_name:"Rock"
  }
 }
}

So upon hitting send, I’m getting below response in postman, so I’m not able to get filtered //data instead getting an empty array.



{
"msg": "Successfully gets the filtered users",
"data": [],
"success": true
}

So please tell what should I do to filter data .

2

Hi @R_V ,
you need to use the dot notation for query a subdocument, so in this esample:

db.array.find().pretty()
{
        "_id" : ObjectId("63c01a42232f174edd983fbe"),
        "unique_key" : "1",
        "user_form" : {
                "user_details" : {
                        "first_name" : "Tely",
                        "last_name" : "Zed"
                }
        }
}
{
        "_id" : ObjectId("63c01a42232f174edd983fbf"),
        "unique_key" : "2",
        "user_form" : {
                "user_details" : {
                        "first_name" : "Rock",
                        "last_name" : "Monty"
                }
        }
}

> db.array.aggregate([{$match:{"user_form.user_details.first_name":"Rock"}}]).pretty()
{
        "_id" : ObjectId("63c01a42232f174edd983fbf"),
        "unique_key" : "2",
        "user_form" : {
                "user_details" : {
                        "first_name" : "Rock",
                        "last_name" : "Monty"
                }
        }
}

Hoping is it useful!!

Regards

2 Likes
3

Hi @Fabio_Ramohitaj , I’ve tried doing it by dot notation too but it still giving the same empty array.

4

Hi @Fabio_Ramohitaj ,
The mistake I did was I kept a space in "first_name" like "first_name " while inserting the document, so that’s why I wasn’t able to get filtered data by dot notation method which I tried earlier as well ,so later upon finding the mistake I get the answer. Thank you.

5

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