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cursor.comment()

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Definition定义

cursor.comment()
Important

mongosh Method

This page documents a mongosh method. This is not the documentation for a language-specific driver, such as Node.js.

For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.

Adds a comment field to the query.向查询中添加comment字段。

cursor.comment() has the following syntax:具有以下语法：

cursor.comment( <string> )

comment() has the following parameter:具有以下参数：

Parameter参数Type类型Description描述
commentstringThe comment to apply to the query.要应用于查询的注释。

Behavior行为

comment() associates a comment string with the find operation. 将注释字符串与查找操作相关联。This can make it easier to track a particular query in the following diagnostic outputs:这样可以更容易地跟踪以下诊断输出中的特定查询：

See configure log verbosity for the mongod log, the Database Profiler tutorial, or the db.currentOp() command.请参阅mongod日志的配置日志详细信息、数据库探查器教程或db.currentOp()命令。

Example实例

The following operation attaches a comment to a query on the restaurants collection:以下操作将注释附加到有关restaurants集合的查询中：

db.restaurants.find(
   { "borough" : "Manhattan" }
).comment( "Find all Manhattan restaurants" )

Output Examples输出示例

system.profile

The following is an excerpt from the system.profile:以下是system.profile的摘录：

{
   "op" : "query",
   "ns" : "guidebook.restaurant",
   "query" : {
      "find" : "restaurant",
      "filter" : {
         "borough" : "Manhattan"
      },
      "comment" : "Find all Manhattan restaurants"
   },
   ...
}

mongod log

The following is an excerpt from the mongod log. It has been formatted for readability.以下是mongod日志的摘录。为便于阅读，已对其进行了格式化。

Important

The verbosity level for QUERY must be greater than 0. QUERY的详细级别必须大于0。See Configure Log Verbosity Levels请参阅配置日志详细级别

2015-11-23T13:09:16.202-05:00 I COMMAND  [conn1]
   command guidebook.restaurant command: find {
      find: "restaurant",
      filter: { "borough" : "Manhattan" },
      comment: "Find all Manhattan restaurants"
   }
   ...

db.currentOp()

Suppose the following operation is currently running on a mongod instance:假设以下操作当前正在mongod实例上运行：

db.restaurants.find(
   { "borough" : "Manhattan" }
).comment("Find all Manhattan restaurants")

Running the db.currentOp() command returns the following:运行db.currentOp()命令会返回以下内容：

{
   "inprog" : [
      {
         "host" : "198.51.100.1:27017",
         "desc" : "conn3",
         "connectionId" : 3,
         ...

         "op" : "query",
         "ns" : "test.$cmd",
         "command" : {
            "find" : "restaurants",
            "filter" : {
               "borough" : "Manhattan"
            },
            "comment" : "Find all Manhattan restaurants",
            "$db" : "test"
         },
         "numYields" : 0,
         ...
      }
   ],
   "ok" : 1
}