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db.collection.insert()

Definition

db.collection.insert()

mongo Shell Method

This page documents the mongo shell method, and does not refer to the MongoDB Node.js driver (or any other driver) method. For corresponding MongoDB driver API, refer to your specific MongoDB driver documentation instead.

Inserts a document or documents into a collection.

The insert() method has the following syntax:

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db.collection.insert(
   <document or array of documents>,
   {
     writeConcern: <document>,
     ordered: <boolean>
   }
)

Parameter	Type	Description
document	document or array	A document or array of documents to insert into the collection.
writeConcern	document	Optional. A document expressing the write concern. Omit to use the default write concern. See Write Concern. Do not explicitly set the write concern for the operation if run in a transaction. To use write concern with transactions, see Transactions and Write Concern.
ordered	boolean	Optional. If true, perform an ordered insert of the documents in the array, and if an error occurs with one of documents, MongoDB will return without processing the remaining documents in the array. If false, perform an unordered insert, and if an error occurs with one of documents, continue processing the remaining documents in the array. Defaults to true.

The insert() returns an object that contains the status of the operation.

Returns:

• A WriteResult object for single inserts.
• A BulkWriteResult object for bulk inserts.

Behaviors

Write Concern

The insert() method uses the insert command, which uses the default write concern. To specify a different write concern, include the write concern in the options parameter.

Create Collection

If the collection does not exist, then the insert() method will create the collection.

_id Field

If the document does not specify an _id field, then MongoDB will add the _id field and assign a unique ObjectId for the document before inserting. Most drivers create an ObjectId and insert the _id field, but the mongod will create and populate the _id if the driver or application does not.

If the document contains an _id field, the _id value must be unique within the collection to avoid duplicate key error.

Transactions

db.collection.insert() can be used inside multi-document transactions.

Important

In most cases, multi-document transaction incurs a greater performance cost over single document writes, and the availability of multi-document transactions should not be a replacement for effective schema design. For many scenarios, the denormalized data model (embedded documents and arrays) will continue to be optimal for your data and use cases. That is, for many scenarios, modeling your data appropriately will minimize the need for multi-document transactions.

For additional transactions usage considerations (such as runtime limit and oplog size limit), see also Production Considerations.

Collection Creation in Transactions

Starting in MongoDB 4.4 with feature compatibility version (fcv) "4.4", you can create collections and indexes inside a multi-document transaction if the transaction is not a cross-shard write transaction.

As such, for feature compatibility version (fcv) "4.4" and greater, if you specify an insert on a non-existing collection in a transaction, the collection is implicitly created.

If the feature compatibility version (fcv) is "4.2" or less, the operation must be against an existing collection.

See also

Create Collections and Indexes In a Transaction

Write Concerns and Transactions

Do not explicitly set the write concern for the operation if run in a transaction. To use write concern with transactions, see Transactions and Write Concern.

Examples

The following examples insert documents into the products collection. If the collection does not exist, the insert() method creates the collection.

Insert a Document without Specifying an _id Field

In the following example, the document passed to the insert() method does not contain the _id field:

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db.products.insert( { item: "card", qty: 15 } )

During the insert, mongod will create the _id field and assign it a unique ObjectId value, as verified by the inserted document:

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{ "_id" : ObjectId("5063114bd386d8fadbd6b004"), "item" : "card", "qty" : 15 }

The ObjectId values are specific to the machine and time when the operation is run. As such, your values may differ from those in the example.

Insert a Document Specifying an _id Field

In the following example, the document passed to the insert() method includes the _id field. The value of _id must be unique within the collection to avoid duplicate key error.

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db.products.insert( { _id: 10, item: "box", qty: 20 } )

The operation inserts the following document in the products collection:

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{ "_id" : 10, "item" : "box", "qty" : 20 }

Insert Multiple Documents

The following example performs a bulk insert of three documents by passing an array of documents to the insert() method. By default, MongoDB performs an ordered insert. With ordered inserts, if an error occurs during an insert of one of the documents, MongoDB returns on error without processing the remaining documents in the array.

The documents in the array do not need to have the same fields. For instance, the first document in the array has an _id field and a type field. Because the second and third documents do not contain an _id field, mongod will create the _id field for the second and third documents during the insert:

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db.products.insert(
   [
     { _id: 11, item: "pencil", qty: 50, type: "no.2" },
     { item: "pen", qty: 20 },
     { item: "eraser", qty: 25 }
   ]
)

The operation inserted the following three documents:

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{ "_id" : 11, "item" : "pencil", "qty" : 50, "type" : "no.2" }
{ "_id" : ObjectId("51e0373c6f35bd826f47e9a0"), "item" : "pen", "qty" : 20 }
{ "_id" : ObjectId("51e0373c6f35bd826f47e9a1"), "item" : "eraser", "qty" : 25 }

Perform an Unordered Insert

The following example performs an unordered insert of three documents. With unordered inserts, if an error occurs during an insert of one of the documents, MongoDB continues to insert the remaining documents in the array.

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db.products.insert(
   [
     { _id: 20, item: "lamp", qty: 50, type: "desk" },
     { _id: 21, item: "lamp", qty: 20, type: "floor" },
     { _id: 22, item: "bulk", qty: 100 }
   ],
   { ordered: false }
)

Override Default Write Concern

The following operation to a replica set specifies a write concern of "w: majority" with a wtimeout of 5000 milliseconds such that the method returns after the write propagates to a majority of the voting replica set members or the method times out after 5 seconds.

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db.products.insert(
    { item: "envelopes", qty : 100, type: "Clasp" },
    { writeConcern: { w: "majority", wtimeout: 5000 } }
)

WriteResult

When passed a single document, insert() returns a WriteResult object.

Successful Results

The insert() returns a WriteResult object that contains the status of the operation. Upon success, the WriteResult object contains information on the number of documents inserted:

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WriteResult({ "nInserted" : 1 })

Write Concern Errors

If the insert() method encounters write concern errors, the results include the WriteResult.writeConcernError field:

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WriteResult({
  "nInserted" : 1,
  "writeConcernError"({
     "code" : 64,
     "errmsg" : "waiting for replication timed out",
     "errInfo" : {
       "wtimeout" : true,
       "writeConcern" : {    // Added in MongoDB 4.4
         "w" : "majority",
         "wtimeout" : 100,
         "provenance" : "getLastErrorDefaults"
       }
     }
})

See also

WriteResult.writeConcernError

Errors Unrelated to Write Concern

If the insert() method encounters a non-write concern error, the results include the WriteResult.writeError field:

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WriteResult({
   "nInserted" : 0,
   "writeError" : {
      "code" : 11000,
      "errmsg" : "insertDocument :: caused by :: 11000 E11000 duplicate key error index: test.foo.$_id_  dup key: { : 1.0 }"
   }
})

BulkWriteResult

When passed an array of documents, insert() returns a BulkWriteResult() object. See BulkWriteResult() for details.

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