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db.collection.deleteOne()

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  • Definition
  • Compatibility
  • Syntax
  • Behavior
  • Examples
db.collection.deleteOne()

Important

mongosh Method

This page documents a mongosh method. This is not the documentation for database commands or language-specific drivers, such as Node.js.

For the database command, see the delete command.

For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.

For the legacy mongo shell documentation, refer to the documentation for the corresponding MongoDB Server release:

mongo shell v4.4

Removes a single document from a collection.

Returns:A document containing:
  • A boolean acknowledged as true if the operation ran with write concern or false if write concern was disabled

  • deletedCount containing the number of deleted documents

You can use db.collection.deleteOne() for deployments hosted in the following environments:

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

The deleteOne() method has the following form:

db.collection.deleteOne(
<filter>,
{
writeConcern: <document>,
collation: <document>,
hint: <document|string> // Available starting in MongoDB 4.4
}
)

The deleteOne() method takes the following parameters:

Parameter
Type
Description
filter
document

Specifies deletion criteria using query operators.

Specify an empty document { } to delete the first document returned in the collection.

document

Optional. A document expressing the write concern. Omit to use the default 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.

document

Optional.

Specifies the collation to use for the operation.

Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.

The collation option has the following syntax:

collation: {
locale: <string>,
caseLevel: <boolean>,
caseFirst: <string>,
strength: <int>,
numericOrdering: <boolean>,
alternate: <string>,
maxVariable: <string>,
backwards: <boolean>
}

When specifying collation, the locale field is mandatory; all other collation fields are optional. For descriptions of the fields, see Collation Document.

If the collation is unspecified but the collection has a default collation (see db.createCollection()), the operation uses the collation specified for the collection.

If no collation is specified for the collection or for the operations, MongoDB uses the simple binary comparison used in prior versions for string comparisons.

You cannot specify multiple collations for an operation. For example, you cannot specify different collations per field, or if performing a find with a sort, you cannot use one collation for the find and another for the sort.

document

Optional. A document or string that specifies the index to use to support the query predicate.

The option can take an index specification document or the index name string.

If you specify an index that does not exist, the operation errors.

For an example, see Specify hint for Delete Operations.

New in version 4.4.

db.collection.deleteOne() deletes the first document that matches the filter. Use a field that is part of a unique index such as _id for precise deletions.

To use db.collection.deleteOne() on a sharded collection:

  • If you only target one shard, you can use a partial shard key in the query specification or,

  • You can provide the shard key or the _id field in the query specification.

db.collection.deleteOne() can be used inside distributed 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.

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.

The orders collection has documents with the following structure:

{
_id: ObjectId("563237a41a4d68582c2509da"),
stock: "Brent Crude Futures",
qty: 250,
type: "buy-limit",
limit: 48.90,
creationts: ISODate("2015-11-01T12:30:15Z"),
expiryts: ISODate("2015-11-01T12:35:15Z"),
client: "Crude Traders Inc."
}

The following operation deletes the order with _id: ObjectId("563237a41a4d68582c2509da") :

try {
db.orders.deleteOne( { "_id" : ObjectId("563237a41a4d68582c2509da") } );
} catch (e) {
print(e);
}

The operation returns:

{ "acknowledged" : true, "deletedCount" : 1 }

The following operation deletes the first document with expiryts greater than ISODate("2015-11-01T12:40:15Z")

try {
db.orders.deleteOne( { "expiryts" : { $lt: ISODate("2015-11-01T12:40:15Z") } } );
} catch (e) {
print(e);
}

The operation returns:

{ "acknowledged" : true, "deletedCount" : 1 }

Given a three member replica set, the following operation specifies a w of majority, wtimeout of 100:

try {
db.orders.deleteOne(
{ "_id" : ObjectId("563237a41a4d68582c2509da") },
{ w : "majority", wtimeout : 100 }
);
} catch (e) {
print (e);
}

If the acknowledgment takes longer than the wtimeout limit, the following exception is thrown:

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

Tip

Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.

A collection myColl has the following documents:

{ _id: 1, category: "café", status: "A" }
{ _id: 2, category: "cafe", status: "a" }
{ _id: 3, category: "cafE", status: "a" }

The following operation includes the collation option:

db.myColl.deleteOne(
{ category: "cafe", status: "A" },
{ collation: { locale: "fr", strength: 1 } }
)

New in version 4.4.

In mongosh, create a students collection with the following documents:

db.members.insertMany([
{ "_id" : 1, "student" : "Richard", "grade" : "F", "points" : 0 },
{ "_id" : 2, "student" : "Jane", "grade" : "A", "points" : 60 },
{ "_id" : 3, "student" : "Adam", "grade" : "F", "points" : 0 },
{ "_id" : 4, "student" : "Ronan", "grade" : "D", "points" : 20 },
{ "_id" : 5, "student" : "Noah", "grade" : "F", "points" : 0 },
{ "_id" : 6, "student" : "Henry", "grade" : "A", "points" : 86 }
])

Create the following index on the collection:

db.members.createIndex( { grade: 1 } )

The following delete operation explicitly hints to use the index { grade: 1 }:

db.members.deleteOne(
{ "points": { $lte: 20 }, "grade": "F" },
{ hint: { grade: 1 } }
)

Note

If you specify an index that does not exist, the operation errors.

The delete command returns the following:

{ "acknowledged" : true, "deletedCount" : 1 }

To view the indexes used, you can use the $indexStats pipeline:

db.members.aggregate( [ { $indexStats: { } }, { $sort: { name: 1 } } ] )

The accesses.ops field in the $indexStats output indicates the number of operations that used the index.

Tip

See also:

To delete multiple documents, see db.collection.deleteMany()

←  db.collection.dataSize()db.collection.deleteMany() →