You can use dot(.) notation to read a specific key-value pair from MongoDB collection. Let us first create a collection with documents −
> db.readSpecificKeyValueDemo.insertOne(
... {
... "_id": 100,
... "StudentDetails":
... {
... "StudentFirstName" : "David",
... "StudentLastName" :"Miller",
... "StudentAge":23,
... "StudentCountryName":"US"
... }
... }
... );
{ "acknowledged" : true, "insertedId" : 100 }
Following is the query to display all documents from the collection with the help of find() method −
> db.readSpecificKeyValueDemo.find().pretty();
This will produce the following output −
{
"_id" : 100,
"StudentDetails" : {
"StudentFirstName" : "David",
"StudentLastName" : "Miller",
"StudentAge" : 23,
"StudentCountryName" : "US"
}
}
Following is the query to read a specific key-value pair from a MongoDB collection −
> db.readSpecificKeyValueDemo.find({},{"StudentDetails.StudentCountryName":1}).pretty();
This will produce the following output −
{ "_id" : 100, "StudentDetails" : { "StudentCountryName" : "US" } }