WriteResult()

Definition

WriteResult()

A wrapper that contains the result status of mongosh write methods.

Tip

See:

• db.collection.insert()

• db.collection.update()

• db.collection.remove()

Note

db.collection.insert() and db.collection.update() are deprecated.

The results returned by the replacement methods have a different format. For output similar to WriteResult(), consider using db.collection.bulkWrite().

Compatibility

This method is available in deployments hosted in the following environments:

• MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

• MongoDB Enterprise: The subscription-based, self-managed version of MongoDB

• MongoDB Community: The source-available, free-to-use, and self-managed version of MongoDB

Properties

The WriteResult() has the following properties:

WriteResult.nInserted

The number of documents inserted, excluding upserted documents. See WriteResult.nUpserted for the number of documents inserted through an upsert.

WriteResult.nMatched

The number of documents selected for update. If the update operation results in no change to the document, e.g. $set expression updates the value to the current value, nMatched can be greater than nModified.

WriteResult.nModified

The number of existing documents updated. If the update/replacement operation results in no change to the document, such as setting the value of the field to its current value, nModified can be less than nMatched.

WriteResult.nUpserted

The number of documents inserted by an upsert.

WriteResult._id

The _id of the document inserted by an upsert. Returned only if an upsert results in an insert.

WriteResult.nRemoved

The number of documents removed.

WriteResult.writeError

A document that contains information regarding any error, excluding write concern errors, encountered during the write operation.

WriteResult.writeError.code

An integer value identifying the error.

WriteResult.writeError.errmsg

A description of the error.

WriteResult.writeConcernError

Document describing errors that relate to the write concern.

Changed in version 5.0.30: When WriteResult() is received from mongos, write concern errors are always reported, even when one or more write errors occur. In previous releases, the occurrence of write errors could cause the WriteResult() to not report write concern errors.

Each error document contains the following fields:

WriteResult.writeConcernError.code

An integer value identifying the cause of the write concern error.

WriteResult.writeConcernError.errmsg

A description of the cause of the write concern error.

WriteResult.writeConcernError.errInfo.writeConcern

The write concern object used for the corresponding operation. For information on write concern object fields, see Write Concern Specification.

The write concern object may also contain the following field, indicating the source of the write concern:

WriteResult.writeConcernError.errInfo.writeConcern.provenance

A string value indicating where the write concern originated (known as write concern provenance). The following table shows the possible values for this field and their significance:

Provenance	Description
clientSupplied	The write concern was specified in the application.
customDefault	The write concern originated from a custom defined default value. See setDefaultRWConcern.
getLastErrorDefaults	The write concern originated from the replica set's settings.getLastErrorDefaults field.
implicitDefault	The write concern originated from the server in absence of all other write concern specifications.