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delete

The delete command removes documents from a collection. A single delete command can contain multiple delete specifications. The command cannot operate on capped collections. The remove methods provided by the MongoDB drivers use this command internally.

Changed in version 5.0.

The delete command has the following syntax:

{
delete: <collection>,
deletes: [
{
q : <query>,
limit : <integer>,
collation: <document>,
hint: <document|string>,
comment: <any>
},
...
],
ordered: <boolean>,
writeConcern: { <write concern> },
let: <document> // Added in MongoDB 5.0
}

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.

boolean

Optional. If true, then when a delete statement fails, return without performing the remaining delete statements. If false, then when a delete statement fails, continue with the remaining delete statements, if any. Defaults to true.

document

Optional. A document expressing the write concern of the delete command. 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.

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:

{ <variable_name_1>: <expression_1>,
...,
<variable_name_n>: <expression_n> }

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 ($$) together with your variable name in the form $$<variable_name>. For example: $$targetTotal.

Note

To use a variable to filter results, you must access the variable within the $expr operator.

For a complete MQL example using let and variables, see see Use Variables in let.

New in version 5.0.

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 0 to delete all matching documents or 1 to delete a single document.

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.

New in version 3.4.

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 hint for Delete Operations.

New in version 4.4.

Returns:A document that contains the status of the operation. See Output for details.

All delete operations for a sharded collection that specify the limit: 1 option must include the shard key or the _id field in the query specification. delete operations specifying limit: 1 in a sharded collection which do not contain either the shard key or the _id field return an error.

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.

delete can be used inside multi-document 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, 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.

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 }
Note

All delete operations for a sharded collection that specify the limit: 1 option must include the shard key or the _id field in the query specification. delete operations specifying limit: 1 in a sharded collection which do not contain either the shard key or the _id field return an error.

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 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 }

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 }

New in version 3.4.

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 } }
]
})

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"
}
)

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.insert( [
{ _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" }
} )

The returned document contains a subset of the following fields:

delete.ok

The status of the command.

delete.n

The number of documents deleted.

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.writeErrors.index

An integer that identifies the delete statement in the deletes array, which uses a zero-based index.

delete.writeErrors.code

An integer value identifying the error.

delete.writeErrors.errmsg

A description of the error.

delete.writeConcernError

Document that describe error related to write concern and contains the fields:

delete.writeConcernError.code

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

delete.writeConcernError.errmsg

A description of the cause of the write concern error.

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:

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.

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:

{
"ok" : 1,
"n" : 0,
"writeErrors" : [
{
"index" : 0,
"code" : 10101,
"errmsg" : "can't remove from a capped collection: test.cappedLog"
}
]
}
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