MongoDB Shell

Posted 2020-10-24 onetoinf

简介

MongoDBShell = JavaScirpt解释器 + MongoDB客户端

MongoDB Shell 是 MongoDB 自带的,使用google v8引擎实现的 javascript Shell，随MongoDB—同发布， 它是MonoDB客户端工具，可以在Shell中使用命令与MongoDB实例交互，对数据库的管理操作（CURD、集群配置、状态查看等）都可以通过MongoDBShell来完成。

基本功能

• 执行JavaScript命令

  1 > "hello, world".replace("world", "MongoDB")
  hello, MongoDB
  2 > function factorial(n) {
  ...     if(n <= 1) return 1;
  ...     return factorial(n-1) * n;
  ... }
  3 > factorial(10)
  3628800

• MongoDB客户端一基本命令

  • 连接/切换数据库 -- use dbname;
  • 数据插入 -- db.stu.insert(obj);
  • 数据查询 -- db.stu.find(query);
  • 数据更新 -- db.stu.update(query,obj);
  • 数据删除 -- db.stu.remove(query);

使用技巧

• help查看帮助

  7 > help
      db.help()                    help on db methods
      db.mycoll.help()             help on collection methods
      sh.help()                    sharding helpers
      rs.help()                    replica set helpers
      help admin                   administrative help
      help connect                 connecting to a db help
      help keys                    key shortcuts
      help misc                    misc things to know
      help mr                      mapreduce
  
      show dbs                     show database names
      show collections             show collections in current database
      show users                   show users in current database
      show profile                 show most recent system.profile entries with time >= 1ms
      show logs                    show the accessible logger names
      show log [name]              prints out the last segment of log in memory, 'global' is default
      use <db_name>                set current database
      db.foo.find()                list objects in collection foo
      db.foo.find( { a : 1 } )     list objects in foo where a == 1
      it                           result of the last line evaluated; use to further iterate
      DBQuery.shellBatchSize = x   set default number of items to display on shell
      exit                         quit the mongo shell

• 执行脚本

  1. 直接运行 例如：mongo[--quiet]script.js

  2. 交互式运行 例如：load("script.js")

     准备一个js文档testMongoShell.jg:

     db = connect("localhost:27017"); // 连接数据库
     db = db.getSiblngDB("test");     // 选择数据库
     cursor = db.demo.find();         // 查询集合
     
     while(cursor.hasNext())          // 迭代输出结果
     {
         printjson( cursor.next() )
     }

     直接运行

     # (anaconda3) whoami at iamwho in [~]
     $ mongo --quiet testMongoShell.js 
     { "_id" : ObjectId("5a7863305640374fb2cd5620"), "y" : 10 }
     { "_id" : ObjectId("5a78636d5640374fb2cd5621"), "y" : 10 }
     { "_id" : ObjectId("5a7863915640374fb2cd5622"), "y" : NumberLong(10) }
     
     # (anaconda3) whoami at iamwho in [~]
     $ mongo testMongoShell.js 
     MongoDB shell version v3.4.10
     connecting to: mongodb://127.0.0.1:27017
     MongoDB server version: 3.4.10
     connecting to: localhost:27017
     MongoDB server version: 3.4.10
     { "_id" : ObjectId("5a7863305640374fb2cd5620"), "y" : 10 }
     { "_id" : ObjectId("5a78636d5640374fb2cd5621"), "y" : 10 }
     { "_id" : ObjectId("5a7863915640374fb2cd5622"), "y" : NumberLong(10) }

     交互式运行

     1 > load("testMongoShell.js")
     connecting to: localhost:27017
     MongoDB server version: 3.4.10
     { "_id" : ObjectId("5a7863305640374fb2cd5620"), "y" : 10 }
     { "_id" : ObjectId("5a78636d5640374fb2cd5621"), "y" : 10 }
     { "_id" : ObjectId("5a7863915640374fb2cd5622"), "y" : NumberLong(10) }
     true

• 执行命令行程序

  例如：run("ls")

  2 > run("ls")
  2018-02-05T23:15:05.650+0800 I - [thread1] shell: started program (sh5361):  /bin/ls
  sh5361| 1.json
  sh5361| AnacondaProjects
  sh5361| avimrc
  3 > run("cd avimrc")
  2018-02-05T23:15:27.155+0800 I - [thread1] shell: started program (sh5366):  cd avimrc
  sh5366| Unable to start program cd avimrc: No such file or directory
  255

  似乎也只能运行内置的shell命令,但是也有着很多的限制.

• .mongorc.js 文件

  mongo启动配置文件

  • 文件分为Global和Local,前者在/etc/.mongorc.js,后者在~下面
  • 可以配置命令提示符,具体参考这里

• 编辑复合变量EDITOR

  这个我忽略了,直接在shell配置文件中export一个EDITOR不就行了吗

  在shell中使用edit + fileName or doc;即可

• 更多命令可参考

  这里