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- db.collection.findOneAndDelete()
db.collection.findOneAndDelete()¶
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Definition¶
- db.collection.findOneAndDelete(filter, options)¶
3.2 新版功能.
Deletes a single document based on the filter and sort criteria, returning the deleted document.
The findOneAndDelete() method has the following form:
db.collection.findOneAndDelete( <filter>, { projection: <document>, sort: <document>, maxTimeMS: <number>, collation: <document> } )
The findOneAndDelete() method takes the following parameters:
Parameter Type Description filter document The selection criteria for the update. The same query selectors as in the find() method are available.
Specify an empty document { } to delete the first document returned in the collection.
projection document Optional. A subset of fields to return.
To return all fields in the returned document, omit this parameter.
sort document Optional. Specifies a sorting order for the documents matched by the filter.
See cursor.sort().
maxTimeMS number Optional. Specifies a time limit in milliseconds within which the operation must complete within. Throws an error if the limit is exceeded. collation 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.
3.4 新版功能.
返回: Returns the deleted document.
Behavior¶
findOneAndDelete() deletes the first matching document in the collection that matches the filter. The sort parameter can be used to influence which document is updated.
The projection parameter takes a document in the following form:
{ field1 : < boolean >, field2 : < boolean> ... }
The <boolean> value can be any of the following:
- 1 or true to include the field. The method returns the _id field even if it is not explicitly stated in the projection parameter.
- 0 or false to exclude the field. This can be used on any field, including _id.
Examples¶
Delete A Document¶
The grades collection contains documents similar to the following:
{ _id: 6305, name : "A. MacDyver", "assignment" : 5, "points" : 24 },
{ _id: 6308, name : "B. Batlock", "assignment" : 3, "points" : 22 },
{ _id: 6312, name : "M. Tagnum", "assignment" : 5, "points" : 30 },
{ _id: 6319, name : "R. Stiles", "assignment" : 2, "points" : 12 },
{ _id: 6322, name : "A. MacDyver", "assignment" : 2, "points" : 14 },
{ _id: 6234, name : "R. Stiles", "assignment" : 1, "points" : 10 }
The following operation finds the first document where name : M. Tagnum and deletes it:
db.scores.findOneAndDelete(
{ "name" : "M. Tagnum" }
)
The operation returns the original document that has been deleted:
{ _id: 6312, name: "M. Tagnum", "assignment" : 5, "points" : 30 }
Sort And Delete A Document¶
The grades collection contains documents similar to the following:
{ _id: 6305, name : "A. MacDyver", "assignment" : 5, "points" : 24 },
{ _id: 6308, name : "B. Batlock", "assignment" : 3, "points" : 22 },
{ _id: 6312, name : "M. Tagnum", "assignment" : 5, "points" : 30 },
{ _id: 6319, name : "R. Stiles", "assignment" : 2, "points" : 12 },
{ _id: 6322, name : "A. MacDyver", "assignment" : 2, "points" : 14 },
{ _id: 6234, name : "R. Stiles", "assignment" : 1, "points" : 10 }
The following operation first finds all documents where name : "A. MacDyver". It then sorts by points ascending before deleting the document with the lowest points value:
db.scores.findOneAndDelete(
{ "name" : "A. MacDyver" },
{ sort : { "points" : 1 } }
)
The operation returns the original document that has been deleted:
{ _id: 6322, name: "A. MacDyver", "assignment" : 2, "points" : 14 }
Projecting the Deleted Document¶
The following operation uses projection to only return the _id and assignment fields in the returned document:
db.scores.findOneAndDelete(
{ "name" : "A. MacDyver" },
{ sort : { "points" : 1 }, projection: { "assignment" : 1 } }
)
The operation returns the original document with the assignment and _id fields:
{ _id: 6322, "assignment" : 2 }
Update Document with Time Limit¶
The following operation sets a 5ms time limit to complete the deletion:
try {
db.scores.findOneAndDelete(
{ "name" : "A. MacDyver" },
{ sort : { "points" : 1 }, maxTimeMS : 5 };
);
}
catch(e){
print(e);
}
If the operation exceeds the time limit, it returns:
Error: findAndModifyFailed failed: { "ok" : 0, "errmsg" : "operation exceeded time limit", "code" : 50 }
Specify Collation¶
3.4 新版功能.
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.findOneAndDelete(
{ category: "cafe", status: "a" },
{ collation: { locale: "fr", strength: 1 } }
);
The operation returns the following document:
{ "_id" : 1, "category" : "café", "status" : "A" }