How to push Data into existing Document in MongoDB?

Question

My problem is I want to push data on to a specified position in an array in a MongoDb Document, but when I push the new data it doesn't add it to the right position.

When run this update statement:

collection.update({ "schraenke.name": "Schrank1" }, {
                    $push:
                    {
                        "schraenke": [{
                            "masterbricks": {
                                "sensor1": { value: "test" }
                            }
                        }]
                    }
                });`

The result from the above update is the document:

{
    "_id": "55599876095c6bac18209dfa",
    "name": "Serverraum1",
    "schraenke": [
      {
        "name": "Schrank1",
        "nummer": "1",
        "reihe": "1",
        "masterbricks": {
          "name": "Mastrebrick2.0",
          "uid": "6dKiRt",
          "he": "1-20",
          "sensor1": {
            "name": "Temperatur",
            "uid": "qvf"
          }
        }
      },
      [
        {
          "masterbricks": {
            "sensor1": {
              "value": "test"
            }
          }
        }
      ],

    ]
  }

The value field should be added to "sensor1", but it adds a new array.

My expected result is:

{ 
    "_id": "55599876095c6bac18209dfa", 
    "name": "Serverraum1", 
    "schraenke": [ 
        { 
           "name": "Schrank1", 
           "nummer": "1", 
           "reihe": "1", 
           "masterbricks": { 
               "name": "Mastrebrick2.0", 
               "uid": "6dKiRt", 
               "he": "1-20", 
               "sensor1": { 
                   "name": "Temperatur", 
                   "uid": "qvf", 
                   "value" : "test" 
               } 
           } 
       }, 
   ] 
}

What am I doing wrong?

What is your expected result? Should your value field be an array or just a single value? — bagrat
– bagrat, Commented May 18, 2015 at 8:22
My expecting result is: { "_id": "55599876095c6bac18209dfa", "name": "Serverraum1", "schraenke": [ { "name": "Schrank1", "nummer": "1", "reihe": "1", "masterbricks": { "name": "Mastrebrick2.0", "uid": "6dKiRt", "he": "1-20", "sensor1": { "name": "Temperatur", "uid": "qvf", "value" : "test" } } }, ] } — mk2015
– mk2015, Commented May 18, 2015 at 8:27
so you mean the sensor document must have a value filed which is an array of measured values? — bagrat
– bagrat, Commented May 18, 2015 at 8:58

chridam · Accepted Answer · 2015-05-18 08:26:07Z

Instead of using $push you need to apply the $set operator together with the $ positional operator in your update to push the new document into the right position. The $ positional operator will identify the correct element in the array to update without explicitly specifying the position of the element in the array, thus your final update statement should look like:

db.collection.update({ "schraenke.name": "Schrank1" }, 
    {
        "$set": {
            "schraenke.$.masterbricks.sensor1.value": "test" 
        }
    }
)

Result:

/* 0 */
{
    "_id" : "55599876095c6bac18209dfa",
    "name" : "Serverraum1",
    "schraenke" : [ 
        {
            "name" : "Schrank1",
            "nummer" : "1",
            "reihe" : "1",
            "masterbricks" : {
                "name" : "Mastrebrick2.0",
                "uid" : "6dKiRt",
                "he" : "1-20",
                "sensor1" : {
                    "name" : "Temperatur",
                    "uid" : "qvf",
                    "value" : "test"
                }
            }
        }
    ]
}

Erkan Demirel · Accepted Answer · 2015-05-18 08:21:14Z

0

$push adds the array field with the value as its element.

You should use $Set

collection.update({ "schraenke.name": "Schrank1" }, {
                    $set:
                    {
                        "schraenke": [{
                            "masterbricks": {
                                "sensor1": { value: "test" }
                            }
                        }]
                    }
                });

answered May 18, 2015 at 8:21

Erkan Demirel

4,4021 gold badge27 silver badges43 bronze badges

2 Comments

mk2015 Over a year ago

Your Example overwrite the existing data, dosent add anything to it.

Erkan Demirel Over a year ago

Check @chridam's answer. It should be just overwrite "value" field not the sensor1

Neo-coder · Accepted Answer · 2015-05-18 08:26:49Z

0

If you use $push then "value" : ["test"] array will added into sensor1 using following update query :

db.collectionName.update({"schraenke.name":"Schrank1"},
  {"$push":{"schraenke.$.masterbricks.sensor1.value":"test"}})

Instead of push use $set as mentioned above chridam and used upsert true in set.

answered May 18, 2015 at 8:26

Neo-coder

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3 Comments

bagrat Over a year ago

Do not use the positional operator $ with upsert operations because inserts will use the $ as a field name in the inserted document.

mk2015 Over a year ago

Yes a want to add a new value and the value should not be overwritten, it should create a new value array

mk2015 Over a year ago

My new query is:

collection.update({ "schraenke.name": "Schrank1" }, { $set: { "schraenke.$.masterbricks.sensor1.value": "Test" } }, { upsert: true });

But its overwriting the existing value

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