MongoDB query to access an object in an array

To access an object in an array, use dot notation. Let us create a collection with documents −

> db.demo299.insertOne( ...   { ...      "id":100, ...      "Name":"Robert", ...      "details":[ ...         { ...            "SubjectName":["C++","Python"] ...         }, ...         { ...            "SubjectName":["Spring","Hibernate"] ...         } ...      ] ...   } ...); {    "acknowledged" : true,    "insertedId" : ObjectId("5e4d685a5d93261e4bc9ea4b") } > > > db.demo299.insertOne( ...   { ...      "id":101, ...      "Name":"Adam", ...      "details":[ ...         { ...            "SubjectName":["Python","JSP"] ...         }, ...         { ...            "SubjectName":["Servlet","Operating System"] ...         } ...      ] ...   } ...); {    "acknowledged" : true,    "insertedId" : ObjectId("5e4d685b5d93261e4bc9ea4c") }

Display all documents from a collection with the help of find() method −

> db.demo299.find();

This will produce the following output −

{    "_id" : ObjectId("5e4d685a5d93261e4bc9ea4b"), "id" : 100, "Name" : "Robert", "details" : [       { "SubjectName" : [ "C++", "Python" ] },       { "SubjectName" : [ "Spring", "Hibernate" ] }    ] } {    "_id" : ObjectId("5e4d685b5d93261e4bc9ea4c"), "id" : 101, "Name" : "Adam", "details" : [       { "SubjectName" : [ "Python", "JSP" ] }, { "SubjectName" : [ "Servlet", "Operating System" ] }    ] }

Following is the query to access an object in an array −

> db.demo299.find({"details.SubjectName":"Servlet"});

This will produce the following output −

{    "_id" : ObjectId("5e4d685b5d93261e4bc9ea4c"), "id" : 101, "Name" : "Adam", "details" : [       { "SubjectName" : [ "Python", "JSP" ] }, { "SubjectName" : [ "Servlet", "Operating System" ] }    ] }