Update Field in Exact Element Array in MongoDB

You can update the in exact element array in MongoDB with the help of below statement. The syntax is as follows:

{"yourArrayDocumentName.$.yourNestedArrayDocument.yourPosition":"yourValue"}});

To understand the above syntax, let us create a collection with some documents. The query to create a collection with document is as follows:

> db.updateExactField.insertOne({"ActorId":1,"ActorDetails":[{"ActorName":"Johnny Depp","MovieList":
["The Tourist","Public Enemy"]},
... {"ActorName":"Chris Evans","MovieList":["Captain America","Avengers"]}]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5c6d7f63f2db199c1278e7f1")
}

Now you can display documents from a collection with the help of find() method. The query is as follows:

> db.updateExactField.find().pretty();

The following is the output:

{
   "_id" : ObjectId("5c6d7f63f2db199c1278e7f1"),
   "ActorId" : 1,
   "ActorDetails" : [
      {
         "ActorName" : "Johnny Depp",
         "MovieList" : [
            "The Tourist",
            "Public Enemy"
         ]
      },
      {
         "ActorName" : "Chris Evans",
         "MovieList" : [
            "Captain America",
            "Avengers"
         ]
      }
   ]
}

Case 1: Here, update with exact array elements i.e. position 3rd, which is index 2 because array starts from 0. The query is as follows:

> db.updateExactField.update(
... {"ActorDetails.ActorName":"Chris Evans"},
... {$set:
... {"ActorDetails.$.MovieList.2":"Avengers:Infinity War"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

Let us display the document from the collection with the help of find(). The query is as follows:

> db.updateExactField.find().pretty();

The following is the output:

{
   "_id" : ObjectId("5c6d7f63f2db199c1278e7f1"),
   "ActorId" : 1,
   "ActorDetails" : [
      {
         "ActorName" : "Johnny Depp",
         "MovieList" : [
            "The Tourist",
            "Public Enemy"
         ]
      },
      {
         "ActorName" : "Chris Evans",
         "MovieList" : [
            "Captain America",
            "Avengers",
            "Avengers:Infinity War"
         ]
      }
   ]
}

Look at the above output, the value “Avengers:Infinite War” is at position 3rd i.e. index 2.

Case 2: Let us now update with index 1 i.e. position 2nd. The query is as follows:

> db.updateExactField.update( {"ActorDetails.ActorName":"Chris Evans"}, {$set:
{"ActorDetails.$.MovieList.1":"Gifted"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

Let us check the document from a collection with the help of find() method. The query is as follows:

> db.updateExactField.find().pretty();

The following is the output:

{
   "_id" : ObjectId("5c6d7f63f2db199c1278e7f1"),
   "ActorId" : 1,
   "ActorDetails" : [
      {
         "ActorName" : "Johnny Depp",
         "MovieList" : [
            "The Tourist",
            "Public Enemy"
         ]
      },
      {
         "ActorName" : "Chris Evans",
         "MovieList" : [
            "Captain America",
            "Gifted",
            "Avengers:Infinity War"
         ]
      }
   ]
}

Look at the above sample output, the value “Gifted” is at position 2 i.e. index 1.