db.createCollection() (mongosh method方法)

Optional. 可选。Configuration options for creating a:用于创建的配置选项：

• Capped collection封顶集合
• Clustered collection集群集合
• View视图

Optional. 可选。The name of the field which contains metadata in each time series document. The metadata in the specified field should be data that is used to label a unique series of documents. The metadata should rarely, if ever, change.每个时间序列文档中包含元数据的字段的名称。指定字段中的元数据应该是用于标记一系列唯一文档的数据。元数据应该很少（如果有的话）发生变化。

The name of the specified field may not be _id or the same as the timeseries.timeField. The field can be of any type except array.指定字段的名称不能是_id，也不能与timeseries.timeField相同。字段可以是除数组之外的任何类型。

Optional, 可选。do not use if setting bucketRoundingSeconds and bucketMaxSpanSeconds. Possible values are seconds (default), minutes, and hours.如果设置bucketRoundingSeconds和bucketMaxSpanSeconds，则不要使用。可能的值是seconds（默认值）、minutes和hours。

Set granularity to the value that most closely matches the time between consecutive incoming timestamps. This improves performance by optimizing how MongoDB internally stores data in the collection.将granularity设置为与连续传入时间戳之间的时间最接近的值。这通过优化MongoDB在集合中内部存储数据的方式来提高性能。

For more information on granularity and bucket intervals, see Set Granularity for Time Series Data.有关粒度和桶间隔的更多信息，请参阅设置时间序列数据的粒度。

Optional, 可选。used with bucketRoundingSeconds as an alternative to granularity. Sets the maximum time between timestamps in the same bucket. Possible values are 1-31536000. 与bucketRoundingSeconds一起使用，作为granularity的替代方案。设置同一桶中时间戳之间的最大时间间隔。可能的值为1-31536000。If you set bucketMaxSpanSeconds, you must set bucketRoundingSeconds to the same value.如果设置bucketMaxSpanSeconds，则必须将bucketRoundingSeconds设置为相同的值。

To downgrade below MongoDB 6.3, you must either modify the collection to use the corresponding granularity value, or drop the collection. 要降级到MongoDB 6.3以下，您必须修改集合以使用相应的granularity值，或者删除集合。For details, see collMod.有关详细信息，请参阅collMod。

Optional, 可选。used with bucketMaxSpanSeconds as an alternative to granularity. Sets the number of seconds to round down by when MongoDB sets the minimum timestamp for a new bucket. 与bucketMaxSpanSeconds一起使用，作为granularity的替代方案。设置MongoDB为新桶设置最小时间戳时四舍五入的秒数。Must be equal to bucketMaxSpanSeconds.必须等于bucketMaxSpanSeconds。

For example, setting both parameters to 1800 rounds new buckets down to the nearest 30 minutes. 例如，将这两个参数都设置为1800，将新桶四舍五入到最接近的30分钟。If a document with a time of 2023-03-27T18:24:35Z does not fit an existing bucket, MongoDB creates a new bucket with a minimum time of 2023-03-27T18:00:00Z and a maximum time of 2023-03-27T18:30:00Z.如果时间为2023-03-27T18:24:35Z的文档不适合现有的桶，MongoDB将创建一个最小时间为2023:03-27T18:00:00Z、最大时间为2023-103-27T18:30:00Z的新桶。

Optional. 可选。Specifies the seconds after which documents in a time series collection or clustered collection expire. MongoDB deletes expired documents automatically.指定时间序列集合或群集集合中的文档过期的秒数。MongoDB会自动删除过期的文档。

For clustered collections, the documents are deleted automatically based on the clustered index key _id and the values must be date types. See TTL Indexes.对于聚集集合，文档将根据聚集索引键_id自动删除，并且值必须是日期类型。请参阅TTL索引。

Starting in MongoDB 5.3, you can create a collection with a clustered index. 从MongoDB 5.3开始，您可以创建一个具有聚集索引的集合。Clustered indexes are stored in the same WiredTiger file as the collection. 聚集索引与集合存储在同一个WiredTiger文件中。The resulting collection is called a clustered collection.生成的集合称为集群集合。

The clusteredIndex field has the following syntax:clusteredIndex字段具有以下语法：

clusteredIndex: {
   key: <object>,
   unique: <boolean>,
   name: <string>
}

key

Required. The clustered index key field. Must be set to { _id: 1 }. 必修的。聚集索引键字段。必须设置为{ _id: 1 }。The default value for the _id field is an automatically generated unique object identifier, but you can set your own clustered index key values._id字段的默认值是自动生成的唯一对象标识符，但您可以设置自己的聚集索引键值。

unique

Required. Must be set to true. A unique index indicates the collection will not accept inserted or updated documents where the clustered index key value matches an existing value in the index.必修的。必须设置为true。唯一索引表示集合将不接受聚集索引键值与索引中现有值匹配的插入或更新文档。

name

Optional. A name that uniquely identifies the clustered index.可选。唯一标识聚集索引的名称。

Optional.可选。

Starting in MongoDB 6.0, you can use change stream events to output the version of a document before and after changes (the document pre- and post-images):从MongoDB 6.0开始，您可以使用更改流事件输出更改前后的文档版本（文档前后映像）：

• The pre-image is the document before it was replaced, updated, or deleted. There is no pre-image for an inserted document.前映像是替换、更新或删除之前的文档。插入的文档没有先映像。
• The post-image is the document after it was inserted, replaced, or updated. There is no post-image for a deleted document.后映像是插入、替换或更新后的文档。已删除文档没有后映像。
• Enable changeStreamPreAndPostImages for a collection using db.createCollection(), create, or collMod.使用db.createCollection()、create或collMod为集合启用changeStreamPreAndPostImages。

changeStreamPreAndPostImages has the following syntax:具有以下语法：

changeStreamPreAndPostImages: {
   enabled: <boolean>
}

To enable change stream pre- and post-images for the collection, set enabled to true.要为集合启用更改流前映像和后映像，请将enabled设置为true。

For complete examples with the change stream output, see Change Streams with Document Pre- and Post-Images.有关更改流输出的完整示例，请参阅使用文档前后映像更改流。

For a db.createCollection() example on this page, see Create a Collection with Change Stream Pre- and Post-Images for Documents.有关此页面上的db.createCollection()示例，请参阅使用更改流为文档创建前后映像的集合。

Optional. 可选。Available for the WiredTiger storage engine only.仅适用于WiredTiger存储引擎。

Allows users to specify configuration to the storage engine on a per-collection basis when creating a collection. The value of the storageEngine option should take the following form:允许用户在创建集合时基于每个集合指定存储引擎的配置。storageEngine选项的值应采用以下形式：

{ <storage-engine-name>: <options> }

Storage engine configuration specified when creating collections are validated and logged to the oplog during replication to support replica sets with members that use different storage engines.在复制过程中，创建集合时指定的存储引擎配置会被验证并记录到oplog中，以支持使用不同存储引擎的成员的副本集。

Starting in MongoDB 7.2, you can't specify wiredTiger storage engine encryption options when you create a collection with db.createCollection(). 从MongoDB 7.2开始，当您使用db.createCollection()创建集合时，您不能指定wiredTiger存储引擎加密选项。To configure encryption for the WiredTiger storage engine, see Encryption at Rest.要为WiredTiger存储引擎配置加密，请参阅静态加密。

For details, see Specify Storage Engine Options.有关详细信息，请参阅指定存储引擎选项。

Optional. 可选。Allows users to specify validation rules or expressions for the collection.允许用户为集合指定验证规则或表达式。

The validator option takes a document that specifies the validation rules or expressions. validator选项接受一个指定验证规则或表达式的文档。You can specify the expressions using the same operators as the query operators with the exception of $near, $nearSphere, $text, and $where.您可以使用与查询运算符相同的运算符指定表达式，但$near、$nearSphere、$text和$where除外。

To learn how to create a collection with schema validation, see Specify JSON Schema Validation.要了解如何使用模式验证创建集合，请参阅指定JSON模式验证。

Optional. 可选。Determines how strictly MongoDB applies the validation rules to existing documents during an update.确定MongoDB在更新期间对现有文档应用验证规则的严格程度。

"off"

No validation for inserts or updates.对插入或更新不进行验证。

"strict"

Default Apply validation rules to all inserts and all updates.默认将验证规则应用于所有插入和所有更新。

"moderate"

Apply validation rules to inserts and to updates on existing valid documents. Do not apply rules to updates on existing invalid documents.将验证规则应用于现有有效文档的插入和更新。不要对现有无效文档的更新应用规则。

To see an example that uses validationLevel, see Specify Validation Level for Existing Documents.要查看使用validationLevel的示例，请参阅为现有文档指定验证级别。

Optional. 可选。Determines whether to error on invalid documents or just warn about the violations but allow invalid documents to be inserted.确定是对无效文档出错，还是仅警告违规行为但允许插入无效文档。

IMPORTANT:重要： Validation of documents only applies to those documents as determined by the validationLevel.文件验证仅适用于validationLevel确定的文件。

To see an example that uses validationAction, see Choose How to Handle Invalid Documents.要查看使用validationAction的示例，请参阅选择如何处理无效文档。

Optional. 可选。Allows users to specify a default configuration for indexes when creating a collection.允许用户在创建集合时为索引指定默认配置。

The indexOptionDefaults option accepts a storageEngine document, which should take the following form:indexOptionDefaults选项接受storageEngine文档，该文档应采用以下形式：

{ <storage-engine-name>: <options> }

Storage engine configuration specified when creating indexes are validated and logged to the oplog during replication to support replica sets with members that use different storage engines.在复制过程中，创建索引时指定的存储引擎配置将被验证并记录到oplog中，以支持使用不同存储引擎的成员的副本集。

Specifies the default collation for the collection.指定集合的默认排序规则。

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

The collation option has the following syntax:排序规则选项具有以下语法：

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.指定排序规则时，locale字段是必填的；所有其他排序字段都是可选的。有关字段的描述，请参阅排序规则文档。

If you specify a collation at the collection level:如果在集合级别指定排序规则：

• Indexes on that collection will be created with that collation unless the index creation operation explicitly specify a different collation.除非索引创建操作明确指定了其他排序规则，否则将使用该排序规则创建该集合上的索引。

• Operations on that collection use the collection's default collation unless they explicitly specify a different collation.对该集合的操作使用该集合的默认排序规则，除非它们明确指定了其他排序规则。

  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.不能为操作指定多个排序规则。例如，您不能为每个字段指定不同的排序规则，或者如果使用排序执行查找，则不能对查找使用一个排序规则，对排序使用另一个。

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.如果没有为集合或操作指定排序规则，MongoDB将使用以前版本中用于字符串比较的简单二进制比较。

For a collection, you can only specify the collation during the collection creation. Once set, you cannot modify the collection's default collation.对于集合，您只能在创建集合时指定排序规则。设置后，您将无法修改集合的默认排序规则。

For an example, see Specify Collation.例如，请参阅指定排序规则。

Optional. 可选。A document that expresses the write concern for the operation. Omit to use the default write concern.一份表达操作写入关注的文档。省略使用默认写入关注。

When issued on a sharded cluster, mongos converts the write concern of the create command and its helper db.createCollection() to "majority".当在分片集群上发出时，mongos会将create命令及其助手db.createCollection()的写关注转换为"majority"。

createCollection on the database, or数据库上的createCollection或者

insert on the collection to create要创建的集合上的insert

convertToCapped for the collection集合上的convertToCapped以及

createCollection on the database数据库上的createCollection

createCollection on the database.数据库上的createCollection

However, if the user has the createCollection on the database and find on the view to create, the user must also have the following additional permissions:但是，如果用户在数据库上拥有createCollection，并在要创建的视图上find，则用户还必须具有以下附加权限：

• find on the source collection or view.在源代码集合或视图上的find。
• find on any other collections or views referenced in the pipeline, if any.pipeline中引用的任何其他集合或视图（如果有的话）上的find。