MongoDB এর সাথে সাবডকুমেন্টে একটি নির্দিষ্ট আইটেম খুঁজে পাচ্ছেন?

একটি সুডকুমেন্টে একটি নির্দিষ্ট আইটেম পেতে, ডট(.) স্বরলিপি ব্যবহার করুন। আসুন নথি-

> db.demo81.insertOne({"StudentDetails":[{"StudentName":"Carol","StudentSubject":"Java"},{ "StudentName" : "David", "StudentSubject" : "MongoDB" }]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e2bf6ec71bf0181ecc4229d")
}
> db.demo81.insertOne({"StudentDetails":[{"StudentName":"Mike","StudentSubject":"Python"},{ "StudentName" : "David", "StudentSubject" : "C" }]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e2bf70471bf0181ecc4229e")
}
> db.demo81.insertOne({"StudentDetails":[{"StudentName":"Jace","StudentSubject":"C++"},{    "StudentName" : "John", "StudentSubject" : "MySQL" }]});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e2bf72071bf0181ecc4229f")
}

Find() পদ্ধতি -

> db.demo81.find();

এটি নিম্নলিখিত আউটপুট −

{
   "_id" : ObjectId("5e2bf6ec71bf0181ecc4229d"), "StudentDetails" : [
      { "StudentName" : "Carol", "StudentSubject" : "Java" },
      {"StudentName" : "David", "StudentSubject" : "MongoDB" }
   ]
}
{
   "_id" : ObjectId("5e2bf70471bf0181ecc4229e"), "StudentDetails" : [
      { "StudentName" : "Mike", "StudentSubject" : "Python" },
      { "StudentName" : "David", "StudentSubject" : "C" }
   ]
}
{
   "_id" : ObjectId("5e2bf72071bf0181ecc4229f"), "StudentDetails" : [
      { "StudentName" : "Jace", "StudentSubject" : "C++" },
      { "StudentName" : "John", "StudentSubject" : "MySQL" }
   ] 
}

MongoDB −

> db.demo81.find({"StudentDetails.StudentSubject":"MongoDB"});

এটি নিম্নলিখিত আউটপুট −

{ "_id" : ObjectId("5e2bf6ec71bf0181ecc4229d"), "StudentDetails" : [ { "StudentName" : "Carol", "StudentSubject" : "Java" }, { "StudentName" : "David", "StudentSubject" : "MongoDB" } ] }