mongodb - What's the difference between insert(), insertOne(), and insertMany() method?

Question

What's the difference between insert(), insertOne(), and insertMany() methods on MongoDB. In what situation should I use each one?

I read the docs, but it's not clear when use each one.

Answer 1

What's the difference between insert(), insertOne() and insertMany() methods on MongoDB

• db.collection.insert() as mentioned in the documentation inserts a document or documents into a collection and returns a WriteResult object for single inserts and a BulkWriteResult object for bulk inserts.

  > var d = db.collection.insert({"b": 3})
  > d
  WriteResult({ "nInserted" : 1 })
  > var d2 = db.collection.insert([{"b": 3}, {'c': 4}])
  > d2
  BulkWriteResult({
          "writeErrors" : [ ],
          "writeConcernErrors" : [ ],
          "nInserted" : 2,
          "nUpserted" : 0,
          "nMatched" : 0,
          "nModified" : 0,
          "nRemoved" : 0,
          "upserted" : [ ]
  })
  

• db.collection.insertOne() as mentioned in the documentation inserts a document into a collection and returns a document which look like this:

  > var document = db.collection.insertOne({"a": 3})
  > document
  {
          "acknowledged" : true,
          "insertedId" : ObjectId("571a218011a82a1d94c02333")
  }
  

• db.collection.insertMany() inserts multiple documents into a collection and returns a document that looks like this:

  > var res = db.collection.insertMany([{"b": 3}, {'c': 4}])
  > res
  {
          "acknowledged" : true,
          "insertedIds" : [
                  ObjectId("571a22a911a82a1d94c02337"),
                  ObjectId("571a22a911a82a1d94c02338")
          ]
  }
  

In what situation should I use each one?

The insert() method is deprecated in major driver so you should use the the .insertOne() method whenever you want to insert a single document into your collection and the .insertMany when you want to insert multiple documents into your collection. Of course this is not mentioned in the documentation but the fact is that nobody really writes an application in the shell. The same thing applies to updateOne, updateMany, deleteOne, deleteMany, findOneAndDelete, findOneAndUpdate and findOneAndReplace. See Write Operations Overview.