SubDocument updates in mongodb using node

Question

SubDocument updates in mongodb using node

I have collection structure like this.

application_data: {
  name : A,
  site : B,
  location : [
    { key1 : value1, key2 : value2},
    { key3 : value3, key4 : value4}
  ]
}

Now I want to add a another array to "location" as a sub document so that my location becomes

location : [
  { key1 : value1, key2 : value2},
  { key3 : value3, key4 : value4, key5 :[{subkey1:subvalue1, subkey2:subvalue2}]}
]

I tried $push & $addToSet which did not help me. Can somebody help me? Helpful if you explain an example using nodejs.

node.js
mongodb

Answer 1

What you'r actually trying to do is to add new field to an existing subdocument. You can do it using $set and positional operator $:

db.applications.update({
  name: 'A', // querying for parent document
  'location.key3': 'value3' // querying for an exact subdocument to add new field to
}, {
  $set: {
    'location.$.key5': [{
      subkey1: 'subvalue1',
      subkey2: 'subvalue2'
    }]
  }
})

You can achieve the same result using $push or $addToSet, which is better if you want to add more than one subsubdocument to 'location.key5':

db.applications.update({
  name: 'A',
  'location.key3': 'value3'
}, {
  $push: {
    'location.$.key5': {
      subkey1: 'subvalue1',
      subkey2: 'subvalue2'
    }
  }
})

or

db.applications.update({
  name: 'A',
  'location.key3': 'value3'
}, {
  $addToSet: {
    'location.$.key5': {
      subkey1: 'subvalue1',
      subkey2: 'subvalue2'
    }
  }
})

See Update Documents in an Array for more info.