delete
Definition
delete
The
delete
command removes documents from a collection. A singledelete
command can contain multiple delete specifications. The delete methods provided by the MongoDB drivers use this command internally.Changed in version 5.0.
Tip
In
mongosh
, this command can also be run through thedeleteOne()
,deleteMany()
, andfindOneAndDelete()
helper methods.Helper methods are convenient for
mongosh
users, but they may not return the same level of information as database commands. In cases where the convenience is not needed or the additional return fields are required, use the database command.Returns: A document that contains the status of the operation. See Output for details.
Syntax
The command has the following syntax:
db.runCommand( { delete: <collection>, deletes: [ { q : <query>, limit : <integer>, collation: <document>, hint: <document|string> }, ... ], comment: <any>, let: <document>, // Added in MongoDB 5.0 ordered: <boolean>, writeConcern: { <write concern> }, maxTimeMS: <integer> } )
Command Fields
The command takes the following fields:
Field | Type | Description | |||
---|---|---|---|---|---|
string | The name of the target collection. | ||||
array | An array of one or more delete statements to perform in the named collection. | ||||
comment | any | Optional. A user-provided comment to attach to this command. Once set, this comment appears alongside records of this command in the following locations:
A comment can be any valid BSON type (string, integer, object, array, etc). New in version 4.4. | |||
document | Optional. Specifies a document with a list of variables. This allows you to improve command readability by separating the variables from the query text. The document syntax is:
The variable is set to the value returned by the expression, and cannot be changed afterwards. To access the value of a variable in the command, use the double
dollar sign prefix ( NoteTo use a variable to filter results, you must access the variable
within the For a complete example using New in version 5.0. | ||||
boolean | Optional. If | ||||
document | Optional. A document expressing the write concern
of the 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. | ||||
maxTimeMS | non-negative integer | Optional. Specifies a time limit in milliseconds.
If you do not specify a value for MongoDB terminates operations that exceed their allotted time limit
using the same mechanism as |
Each element of the deletes
array contains the following fields:
Field | Type | Description | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
document | The query that matches documents to delete. | |||||||||||
integer | The number of matching documents to delete. Specify either a | |||||||||||
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:
When specifying collation, the If the collation is unspecified but the collection has a
default collation (see 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 or string | 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 New in version 4.4. |
Behavior
Sharded Collections
To use delete
operations for a sharded
collection that specify the limit: 1
option:
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.
Limits
The total size of all the queries (i.e. the q
field values) in the
deletes
array must be less than or equal to the maximum
BSON document size.
The total number of delete documents in the deletes
array must be
less than or equal to the maximum bulk size.
Transactions
delete 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.
Examples
Limit the Number of Documents Deleted
The following example deletes from the orders
collection one
document that has the status
equal to D
by specifying the
limit
of 1
:
db.runCommand( { delete: "orders", deletes: [ { q: { status: "D" }, limit: 1 } ] } )
The returned document shows that the command deleted 1
document.
See Output for details.
{ "ok" : 1, "n" : 1 }
Delete All Documents That Match a Condition
The following example deletes from the orders
collection all
documents that have the status
equal to D
by specifying the
limit
of 0
:
db.runCommand( { delete: "orders", deletes: [ { q: { status: "D" }, limit: 0 } ], writeConcern: { w: "majority", wtimeout: 5000 } } )
The returned document shows that the command found and deleted 13
documents. See Output for details.
{ "ok" : 1, "n" : 13 }
Delete All Documents from a Collection
Delete all documents in the orders
collection by specifying an
empty query condition and a limit
of 0
:
db.runCommand( { delete: "orders", deletes: [ { q: { }, limit: 0 } ], writeConcern: { w: "majority", wtimeout: 5000 } } )
The returned document shows that the command found and deleted 35
documents in total. See Output for details.
{ "ok" : 1, "n" : 35 }
Bulk Delete
The following example performs multiple delete operations on the
orders
collection:
db.runCommand( { delete: "orders", deletes: [ { q: { status: "D" }, limit: 0 }, { q: { cust_num: 99999, item: "abc123", status: "A" }, limit: 1 } ], ordered: false, writeConcern: { w: 1 } } )
The returned document shows that the command found and deleted 21
documents in total for the two delete statements. See
Output for details.
{ "ok" : 1, "n" : 21 }
Specify Collation
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.runCommand({ delete: "myColl", deletes: [ { q: { category: "cafe", status: "a" }, limit: 0, collation: { locale: "fr", strength: 1 } } ] })
Specify hint
for Delete Operations
New in version 4.4.
In mongosh
, create a members
collection
with the following documents:
db.members.insertMany([ { "_id" : 1, "member" : "abc123", "status" : "P", "points" : 0, "misc1" : null, "misc2" : null }, { "_id" : 2, "member" : "xyz123", "status" : "A", "points" : 60, "misc1" : "reminder: ping me at 100pts", "misc2" : "Some random comment" }, { "_id" : 3, "member" : "lmn123", "status" : "P", "points" : 0, "misc1" : null, "misc2" : null }, { "_id" : 4, "member" : "pqr123", "status" : "D", "points" : 20, "misc1" : "Deactivated", "misc2" : null }, { "_id" : 5, "member" : "ijk123", "status" : "P", "points" : 0, "misc1" : null, "misc2" : null }, { "_id" : 6, "member" : "cde123", "status" : "A", "points" : 86, "misc1" : "reminder: ping me at 100pts", "misc2" : "Some random comment" } ])
Create the following indexes on the collection:
db.members.createIndex( { status: 1 } ) db.members.createIndex( { points: 1 } )
The following delete operation explicitly hints to use the index
{ status: 1 }
:
db.runCommand({ delete: "members", deletes: [ { q: { "points": { $lte: 20 }, "status": "P" }, limit: 0, hint: { status: 1 } } ] })
Note
If you specify an index that does not exist, the operation errors.
To see the index used, run explain
on the operation:
db.runCommand( { explain: { delete: "members", deletes: [ { q: { "points": { $lte: 20 }, "status": "P" }, limit: 0, hint: { status: 1 } } ] }, verbosity: "queryPlanner" } )
Use Variables in let
New in version 5.0.
To define variables that you can access elsewhere in the command, use the let option.
Note
To filter results using a variable, you must access the variable
within the $expr
operator.
Create a collection cakeFlavors
:
db.cakeFlavors.insertMany( [ { _id: 1, flavor: "chocolate" }, { _id: 2, flavor: "strawberry" }, { _id: 3, flavor: "cherry" } ] )
The following example defines a targetFlavor
variable in let
and
uses the variable to delete the strawberry cake flavor:
db.runCommand( { delete: db.cakeFlavors.getName(), deletes: [ { q: { $expr: { $eq: [ "$flavor", "$$targetFlavor" ] } }, limit: 1 } ], let : { targetFlavor: "strawberry" } } )
Output
The returned document contains a subset of the following fields:
delete.writeErrors
An array of documents that contains information regarding any error encountered during the delete operation. The
writeErrors
array contains an error document for each delete statement that errors.Each error document contains the following information:
delete.writeConcernError
Document that describe error related to write concern and contains the fields:
delete.writeConcernError.errInfo.writeConcern
New in version 4.4.
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:
delete.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:ProvenanceDescriptionclientSupplied
The write concern was specified in the application.customDefault
The write concern originated from a custom defined default value. SeesetDefaultRWConcern
.getLastErrorDefaults
The write concern originated from the replica set'ssettings.getLastErrorDefaults
field.implicitDefault
The write concern originated from the server in absence of all other write concern specifications.
The following is an example document returned for a successful
delete
command:
{ ok: 1, n: 1 }
The following is an example document returned for a delete
command that encountered an error because it specified a non-existent
index in the hint
field:
{ n: 0, writeErrors: [ { index: 0, code: 2, errmsg: 'error processing query: ns=test.products: hat $eq "bowler"\n' + 'Sort: {}\n' + 'Proj: {}\n' + ' planner returned error :: caused by :: hint provided does not correspond to an existing index' } ], ok: 1 }