db.collection.findOneAndDelete()

Document Match文档匹配

findOneAndDelete() deletes the first matching document in the collection that matches the filter. 删除集合中与filter匹配的第一个匹配文档。The sort parameter can be used to influence which document is deleted.sort参数可用于影响要删除的文档。

Projection

The projection parameter takes a document in the following form:projection参数采用以下形式的文档：

{ field1: <value>, field2: <value> ... }

Sharded Collections分片集合

When using db.collection.findOneAndDelete() against a sharded collection, the query must contain an equality condition on shard key.当对分片集合使用db.collection.findOneAndDelete()时，query必须包含分片键上的相等条件。

Starting in version 4.4, documents in a sharded collection can be missing the shard key fields. 从4.4版开始，分片集合中的文档可能会缺少分片键字段。To target a document that is missing the shard key, you can use the null equality match in conjunction with another filter condition (such as on the _id field). 要将缺少shard键的文档作为目标，可以将null相等匹配与另一个筛选条件（例如在_id字段上）结合使用。For example:例如：

{ _id: <value>, <shardkeyfield>: null } // _id of the document missing shard key

Transactions事务

db.collection.findOneAndDelete() can be used inside multi-document transactions.可以在多文档事务处理中使用。

Do not explicitly set the write concern for the operation if run in a transaction. 如果在事务中运行，请不要显式设置操作的写入关注点。To use write concern with transactions, see Transactions and Write Concern.要将写关注点用于事务，请参阅事务和写关注点。

Delete A Document删除文档

The scores collection contains documents similar to the following:scores集合包含与以下内容类似的文档：

 db.scores.insertMany( [
   { _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:以下操作将查找name : M. Tagnum的第一个文档并将其删除：

db.scores.findOneAndDelete(
   { "name" : "M. Tagnum" }
)

The operation returns the original document that has been deleted:该操作返回已删除的原始文档：

{ _id: 6312, name: "M. Tagnum", "assignment" : 5, "points" : 30 }

Delete A Document Using WriteConcern使用WriteConcern删除文档

The scores collection contains documents similar to the following:scores集合包含与以下内容类似的文档：

db.scores.insertMany( [
   { _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 uses a write concern document inside of the db.collection.findOneAndDelete() method with options:以下操作使用带有选项的db.collection.findOneAndDelete()方法内的写关注点文档：

• w:1 to requests acknowledgment that the write operation has propagated to the standalone mongod or the primary in a replica set.请求确认写入操作已传播到副本集中的独立mongod或主mongod。
• j:true to tell the number of MongoDB instances specified in w:1 to have the delete written to on-disk journel.告诉w:1中指定的要将delete写入磁盘日志的MongoDB实例的数量。
• wtimeout : 1000 to specify a time limit, in milliseconds, for the write concern. 以指定写入问题的时间限制（以毫秒为单位）。wtimeout is only applicable for w values greater than 1.wtimeout仅适用于大于1的w值。

db.scores.findOneAndDelete(
   { name: "A. MacDyver" },
   {
      writeConcern: {
         w : 1,
         j : true,
         wtimeout : 1000
      }
   }
)

The operation returns the following document:该操作返回以下文档：

{ _id: 6305, name: 'A. MacDyver', assignment: 5, points: 24 }

The document is deleted with the writeConcern options specified.使用指定的writeConcern选项删除文档。

Sort And Delete A Document排序并删除文档

The scores collection contains documents similar to the following:scores集合包含与以下内容类似的文档：

db.scores.insertMany( [
   { _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". 以下操作首先查找名称为name : "A. MacDyver"的所有文档。It then sorts by points ascending before deleting the document with the lowest points value:然后按points升序排序，然后删除具有最低点数值的文档：

db.scores.findOneAndDelete(
   { "name" : "A. MacDyver" },
   { sort : { "points" : 1 } }
)

The operation returns the original document that has been deleted:该操作返回已删除的原始文档：

{ _id: 6322, name: "A. MacDyver", "assignment" : 2, "points" : 14 }

Projecting the Deleted Document投影已删除的文档

The following operation uses projection to only return the _id and assignment fields in the returned document:以下操作使用投影仅返回返回文档中的_id和assignment字段：

db.scores.findOneAndDelete(
   { "name" : "A. MacDyver" },
   { sort : { "points" : 1 }, projection: { "assignment" : 1 } }
)

The operation returns the original document with the assignment and _id fields:该操作返回带有assignment和_id字段的原始文档：

{ _id: 6322, "assignment" : 2 }

Update Document with Time Limit更新具有时间限制的文档

The following operation sets a 5ms time limit to complete the deletion:以下操作设置了5ms的时间限制以完成删除：

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:如果操作超过时间限制，则返回：

MongoServerError: operation exceeded time limit: { "ok": 0, "code" : 50, "codeName" : "MaxTimeMSExpired" }

Specify Collation指定排序规则

Collation allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.排序规则允许用户指定特定于语言的字符串比较规则，例如字母大小写和重音标记规则。

A collection myColl has the following documents:集合myColl包含以下文档：

db.myColl.insertMany( [
   { _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:以下操作包括排序规则选项：

db.myColl.findOneAndDelete(
   { category: "cafe", status: "a" },
   { collation: { locale: "fr", strength: 1 } }
);

The operation returns the following document:该操作返回以下文档：

{ "_id" : 1, "category" : "café", "status" : "A" }