mongo执行JavaScript脚本

迷南。 2023-08-17 17:50 118阅读 0赞

> mongo客户端有两种方式与mongodb服务进行交互,一种是mongo shell,一种是执行javascript脚本.mongo shell,平时用的比较多,但是javascript脚本却很少用.前段时间,在一个项目中通过写js脚本批量的更新了一些数据,做一下总结.

## 如何执行 ##

1.  mongo host:port/database /dir/xxxx.js

> 示例: mongo localhost:27017/hr\_assistant index.js 在index.js中先跟mongodb打个招呼,然后打印一下当前的数据库

print('hello mongodb')
    // 打印连接之后的数据库
    print(db);

执行结果:

MongoDB shell version v4.0.11
    connecting to: mongodb://localhost:27017/hr_assistant?gssapiServiceName=mongodb
    Implicit session: session { "id" : UUID("3e0c8e42-57d5-429d-a00d-bad97ec95d73") }
    MongoDB server version: 4.0.11
    hello mongodb
    hr_assistant

1.  上述方式是通过mongo客户端直接执行一个js脚本,也可以在进入客户端的命令行交互中使用load函数去加载一个脚本

实例:

// 进入客户端
    pan@ubuntu18:~/disk/panyanan/blog/mongodb$ mongo localhost:27017/hr_assistant
    MongoDB shell version v4.0.11
    connecting to: mongodb://127.0.0.1:27017/
    // load脚本文件
    > load('index.js')
    hello mongodb
    hr_assistant
    true

> 注意上述两种方式都需要注意脚本的路径问题，最好是在脚本所有文件夹去执行mongo命令，省心，省事．

## js脚本与mongo Shell 的不同 ##

> mongoShell是一个简化版的JavaScript Shell, 可以自由的编写javascript代码,也内置了很多属于mongodb的特有对象及方法,但是在脚本中你无法使用像 show databases、show collections、use test这种命令，需要使用客户端提供函数如db.getCollectionNames()；下面这个表格是常用命令对应的函数

<table> 
 <thead> 
  <tr> 
   <th>commands</th> 
   <th>function</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>show dbs, show databases</td> 
   <td>db.adminCommand('listDatabases')</td> 
  </tr> 
  <tr> 
   <td>use db</td> 
   <td>db = db.getSiblingDB('db')</td> 
  </tr> 
  <tr> 
   <td>show collections</td> 
   <td>db.getCollectionsNames()</td> 
  </tr> 
  <tr> 
   <td>show users</td> 
   <td>db.getUsers()</td> 
  </tr> 
 </tbody> 
</table>

> 还有两个在js脚本中常用的函数，print()/printjson()可以将参数打印到标准输出上。

示例 index.js：

//  因为是--nodb 形式启动的mongo客户端 所以新建一个连接
    const conn = new Mongo('localhost:27017');
    print(`连接: ${conn}`)
    let db = conn.getDB('hr_assistant');
    print(`当前数据库：${db}`);
    const dbs = db.adminCommand('listDatabases');
    print('显示所有的数据库:')
    printjson(dbs);
    const collections = db.getCollectionNames();
    print(`${db}中的collections:`);
    printjson(collections);
    db = db.getSiblingDB('test');
    print(`切换数据库为${db}`);

运行结果:

pan@ubuntu18:~/disk/panyanan/blog/mongodb$ mongo --nodb index.js
    MongoDB shell version v4.0.11
    连接: connection to localhost:27017
    当前数据库：hr_assistant
    显示所有的数据库:
    {
            "databases" : [
                    {
                            "name" : "admin",
                            "sizeOnDisk" : 32768,
                            "empty" : false
                    },
                    {
                            "name" : "config",
                            "sizeOnDisk" : 49152,
                            "empty" : false
                    },
                    {
                            "name" : "hr_assistant",
                            "sizeOnDisk" : 98873344,
                            "empty" : false
                    },
                    {
                            "name" : "local",
                            "sizeOnDisk" : 73728,
                            "empty" : false
                    }
            ],
            "totalSize" : 99028992,
            "ok" : 1
    }
    hr_assistant中的collections:
    [
            "hr_business_call_records",
            "hr_business_info_collection",
            "hr_business_info_follow",
            "hr_business_info_interviewed",
            "hr_business_info_meeting",
            "hr_business_info_planned",
            "hr_business_info_user",
            "hr_business_resume_assessment",
            "hr_business_resume_basic_work",
            "hr_business_resume_basiceducation",
            "hr_business_resume_basichealth",
            "hr_business_resume_basicinfo",
            "hr_business_resume_head_portrait",
            "hr_business_resume_jobobjective",
            "hr_business_resume_percentage",
            "hr_business_resume_workexp",
            "hr_business_sign_list",
            "hr_business_signed_result"
    ]
    切换数据库为test

## 愉快的玩耍 ##

> 了解了如何运行js脚本以及与mongoshell的区别,就可以在js文件中成为一个curdBoy了.因为在js文件中可以使用mongo客户端提供的所有增删改查方法,加上js内置对象/数组的方法,简直是如虎添翼.  
> 下面是个简单的示例

运行结果

pan@ubuntu18:~/disk/panyanan/blog/mongodb$ mongo --nodb curd.js
    MongoDB shell version v4.0.11
    批量插入一写员工
    BulkWriteResult({
            "writeErrors" : [ ],
            "writeConcernErrors" : [ ],
            "nInserted" : 4,
            "nUpserted" : 0,
            "nMatched" : 0,
            "nModified" : 0,
            "nRemoved" : 0,
            "upserted" : [ ]
    })
    获取jack:
    {
            "_id" : ObjectId("5d44fdd70998b36ed6983e6c"),
            "ename" : "Jack",
            "deptno" : 40,
            "job" : "president",
            "mgr" : "",
            "sal" : 3000
    }
    更新薪资后的jack:
    {
            "_id" : ObjectId("5d44fdd70998b36ed6983e6c"),
            "ename" : "Jack",
            "deptno" : 40,
            "job" : "president",
            "mgr" : "",
            "sal" : 5000
    }
    获取所有的员工:
    {
            "_id" : ObjectId("5d44fdd70998b36ed6983e6a"),
            "ename" : "Smith",
            "deptno" : 20,
            "job" : "salesman",
            "mgr" : "",
            "sal" : 800
    }
    {
            "_id" : ObjectId("5d44fdd70998b36ed6983e6b"),
            "ename" : "Peter",
            "deptno" : 30,
            "job" : "manager",
            "mgr" : "",
            "sal" : 1000
    }
    {
            "_id" : ObjectId("5d44fdd70998b36ed6983e6c"),
            "ename" : "Jack",
            "deptno" : 40,
            "job" : "president",
            "mgr" : "",
            "sal" : 5000
    }
    {
            "_id" : ObjectId("5d44fdd70998b36ed6983e6d"),
            "ename" : "Rose",
            "deptno" : 50,
            "job" : "analyst",
            "mgr" : "",
            "sal" : 1500
    }
    更新所有员工的领导为jordan
    {
            "_id" : ObjectId("5d44fdd70998b36ed6983e6a"),
            "ename" : "Smith",
            "deptno" : 20,
            "job" : "salesman",
            "mgr" : "Jordan",
            "sal" : 800
    }
    {
            "_id" : ObjectId("5d44fdd70998b36ed6983e6b"),
            "ename" : "Peter",
            "deptno" : 30,
            "job" : "manager",
            "mgr" : "Jordan",
            "sal" : 1000
    }
    {
            "_id" : ObjectId("5d44fdd70998b36ed6983e6c"),
            "ename" : "Jack",
            "deptno" : 40,
            "job" : "president",
            "mgr" : "Jordan",
            "sal" : 5000
    }
    {
            "_id" : ObjectId("5d44fdd70998b36ed6983e6d"),
            "ename" : "Rose",
            "deptno" : 50,
            "job" : "analyst",
            "mgr" : "Jordan",
            "sal" : 1500
    }
    删除员工:: WriteResult({ "nRemoved" : 4 })

转载于:https://www.cnblogs.com/pandapeter/p/11294232.html