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How to get the child of a MongoDB collection by the key?
To get the child of a collection in MongoDB, use find(). Let us create a collection with documents −
> db.demo305.insertOne(
... {
... _id: 101,
... FirstName : 'Chris',
... details : {
... "0":"102",
... "1":"10001"
... }
... }
...);
{ "acknowledged" : true, "insertedId" : 101 }
> db.demo305.insertOne(
... {
... _id: 102,
... FirstName : 'David',
... details : {
... "0":"103",
... "1":"10002"
... }
... }
...);
{ "acknowledged" : true, "insertedId" : 102 }Display all documents from a collection with the help of find() method −
> db.demo305.find();
This will produce the following output −
{ "_id" : 101, "FirstName" : "Chris", "details" : { "0" : "102", "1" : "10001" } }
{ "_id" : 102, "FirstName" : "David", "details" : { "0" : "103", "1" : "10002" } }Following is the query to get the child of a MongoDB collection by the key −
> db.demo305.find({_id:102},{'details.0':1});This will produce the following output −
{ "_id" : 102, "details" : { "0" : "103" } }
Updated on: 01-Apr-2020
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