Select special fields rather than all in MongoDB

MongoDBDatabaseBig Data Analytics

For this, simply use find(). Set the fields you don’t want to select to 0. Let us create a collection with documents −

> db.demo269.insertOne({StudentId:101,StudentSubject:"MySQL"});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e481caa1627c0c63e7dbab4")
}
> db.demo269.insertOne({StudentId:102,StudentSubject:"Java"});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e481cb11627c0c63e7dbab5")
}
> db.demo269.insertOne({StudentId:103,StudentSubject:"MongoDB"});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e481cb21627c0c63e7dbab6")
}
> db.demo269.insertOne({StudentId:104,StudentSubject:"C"});
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e481cb21627c0c63e7dbab7")
}

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

> db.demo269.find();

This will produce the following output −

{ "_id" : ObjectId("5e481caa1627c0c63e7dbab4"), "StudentId" : 101, "StudentSubject" : "MySQL" }
{ "_id" : ObjectId("5e481cb11627c0c63e7dbab5"), "StudentId" : 102, "StudentSubject" : "Java" }
{ "_id" : ObjectId("5e481cb21627c0c63e7dbab6"), "StudentId" : 103, "StudentSubject" : "MongoDB" }
{ "_id" : ObjectId("5e481cb21627c0c63e7dbab7"), "StudentId" : 104, "StudentSubject" : "C" }

Following is the query to select only specific fields rather than all −

> db.demo269.find({},{"StudentId":0,_id:0});

This will produce the following output −

{ "StudentSubject" : "MySQL" }
{ "StudentSubject" : "Java" }
{ "StudentSubject" : "MongoDB" }
{ "StudentSubject" : "C" }
raja
Published on 31-Mar-2020 08:45:55
Advertisements