use tinker


db.test1.insertOne(
   {
      "StudentId" :1,
      "StudentName" : "Joseph Connor"
   }
)

db.test1.find()

db.test1.insertOne

db.test1.insertOne(
   {
      "StudentId" :1,
      "StudentName" : "Joseph Connor"
   }
)

doc = {
      "StudentId" :1,
      "StudentName" : "Joseph Connor"
}

db.test1.insertOne(doc)

db.test1.find()

if (db.test1.find(doc).count() == 0) { db.test1.insertOne(doc) }

doc2 = {
      "StudentId" :5,
      "StudentName" : "Mary Connor"
}

if (db.test1.find(doc2).count() == 0) { db.test1.insertOne(doc2) }



// remove tinker
show dbs
db.dropDatabase()
show dbs
// create index
db.test1.createIndex( { "StudentId": 1 }, { unique: true } )
// StudentId: 1 => true
doc = {
      "StudentId" :1,
      "StudentName" : "Joseph Connor"
}
doc

db.test1.insertOne(doc)
db.test1.insertOne(doc)

db.test1.insertMany([
   {   "StudentId" :2,
      "GPA": 3.72
   },
   {   "StudentId" :3,
      "GPA": 1.69
   },
   {
      "BCAssetId": "78c22fc6-5dec-11ec-bf63-0242ac130002",
      "BCAssetType": "BCAssetTypeMetadata",
      "BCAssetName": "BCAssetTypeMetadata: MBSEModel",
      "ForBCAssetType": "MBSEModel",
      "Version": {
         "Version": "1.0",
         "Subversion": null,
         "StartTime": "2019-01-13T07:23:13+06:00"
      }
   }
])
db.test1.find()


// Show all information of students majoring in 'CINF'.

db.student.find({"major": "CINF"}, // query
    { "_id": 0 } // projection
)

// Show all information of students majoring in 'CINF'.

db.student.find({"major": "CINF"},
    { "_id": false }
)