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New in version 3.6.版本3.6中的新功能。
db.
aggregate
()¶Runs a specified admin/diagnostic pipeline which does not require an underlying collection. 运行不需要基础集合的指定管理/诊断管道。For aggregations on collection data, see 有关收集数据的聚合,请参阅db.collection.aggregate()
.db.collection.aggregate()
。
The db.aggregate()
method has the following syntax:db.aggregate()
方法语法如下所示:
pipeline
parameter is an array of stages to execute. pipeline
参数是要执行的阶段数组。$currentOp
or $listLocalSessions
.$currentOp
或$listLocalSessions
。options
document can contain the following fields and values:options
文档可以包含以下字段和值:
explain |
boolean |
|
allowDiskUse |
boolean |
|
cursor |
document | cursor field is a document with the field batchSize . cursor 字段的值是具有batchSize 字段的文档。 |
maxTimeMS |
non-negative integer |
|
bypassDocumentValidation |
boolean |
|
readConcern |
document |
|
collation |
document |
Collation
|
hint |
string or document |
Note The
|
comment |
string |
|
writeConcern |
document |
|
$currentOp
$currentOp
的管道¶The following example runs a pipeline with two stages. 下面的示例运行一个包含两个阶段的管道。The first stage runs the 第一阶段运行$currentOp
operation and the second stage filters the results of that operation.$currentOp
操作,第二阶段筛选该操作的结果。