db.collection.insert()
Important
Deprecated mongosh Method
This method is deprecated in mongosh
. For alternative
methods, see Compatibility Changes with Legacy mongo Shell.
Definition
db.collection.insert()
Inserts a document or documents into a collection.
Returns: A WriteResult object for single inserts.
A BulkWriteResult object for bulk inserts.
Syntax
The insert()
method has the following
syntax:
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 If Defaults to |
The insert()
returns an object that
contains the status of the operation.
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 distributed transactions.
Important
In most cases, a distributed transaction incurs a greater performance cost over single document writes, and the availability of distributed 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 distributed transactions.
For additional transactions usage considerations (such as runtime limit and oplog size limit), see also Production Considerations.
Collection Creation in Transactions
You can create collections and indexes inside a distributed transaction if the transaction is not a cross-shard write transaction.
If you specify an insert on a non-existing collection in a transaction, MongoDB creates the collection implicitly.
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.
Oplog Entries
If a db.collection.insert()
operation successfully inserts a document,
the operation adds an entry on the oplog (operations log).
If the operation fails, the operation does not add an entry on the
oplog.
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:
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:
{ "_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.
db.products.insert( { _id: 10, item: "box", qty: 20 } )
The operation inserts the following document in the products
collection:
{ "_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:
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:
{ "_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.
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: 2
with a wtimeout
of 5000
milliseconds. This operation either returns after the write propagates
to both the primary and one secondary, or times out after 5 seconds.
db.products.insert( { item: "envelopes", qty : 100, type: "Clasp" }, { writeConcern: { w: 2, 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:
WriteResult({ "nInserted" : 1 })
Write Concern Errors
If the insert()
method encounters write
concern errors, the results include the
WriteResult.writeConcernError
field:
WriteResult({ "nInserted" : 1, "writeConcernError"({ "code" : 64, "errmsg" : "waiting for replication timed out", "errInfo" : { "wtimeout" : true, "writeConcern" : { "w" : "majority", "wtimeout" : 100, "provenance" : "getLastErrorDefaults" } } })
Errors Unrelated to Write Concern
If the insert()
method encounters a non-write
concern error, the results include the WriteResult.writeError
field:
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.