MongoDB常用命令

前言

mongoDB 最近开始做一些简单的数据查询计算功能，但是因为mongodb用的比较少，对很多的查询方法都不熟悉，因此整理了一些常用的命令，平时工作有需要时候方便查询，当然遇到一些新的也可以进行更新。

管理mongodb

创建管理员

db.createUser( { user: “myUserAdmin”, pwd: “abc123”, roles: [ { role: “userAdminAnyDatabase”, db: “admin” } ] } )

管理员登录

mongo –port 27017 -u “myUserAdmin” -p “abc123” –authenticationDatabase “admin”

其他用户登录

mongo –port 27017 -u “myTester” -p “xyz123” –authenticationDatabase “test”

登入数据库

use nieweb

删除用户

db.dropUser(“dev”) true

创建用户角色

db.createUser({“user”:”dev”,pwd:”dev123”,roles:[“readWrite”]}) Successfully added user: { “user” : “dev”, “roles” : [ “readWrite” ] } show users { “_id” : “nieweb.dev”, “user” : “dev”, “db” : “nieweb”, “roles” : [ { “role” : “readWrite”, “db” : “nieweb” } ] }

配置mongodb

修改mongodb 外部访问的IP权限 /etc/mongod.conf 修改/etc/mongod.conf bingip改为0.0.0.0 或者外网IP

一般查询

查询

MySQL:

SELECT * FROM user

Mongo:

db.user.find()

MySQL:

SELECT * FROM user WHERE name = ‘foobar’

Mongo:

db.user.find({‘name’ : ‘foobar’})

插入

MySQL:

INSERT INTO user (name, age) values (‘foobar’,25)

Mongo:

db.user.insert({‘name’ : ‘foobar’, ‘age’ : 25})

修改集合字段

if you want add a column email on MySQL,you must :

ALTER TABLE user add email varchar(100) comment “邮箱”;

But in Mongo,you can just:

db.user.insert({‘name’ : ‘foobar’, ‘age’ : 25, ‘email’ : ‘foo@bar.com’})

删除表内容

MySQL:

DELETE * FROM user

Mongo:

db.user.remove({})

根据条件删除

MySQL:

DELETE FROM user WHERE age < 30

Mongo:

db.user.remove({‘age’ : {$lt : 30}})

其他比较符号

gt:>; gte : >= ; lt:<; lte : <= ; $ne : !=

更新

MySQL:

UPDATE user SET age = 36 WHERE name = ‘foobar’

Mongo:

db.user.update({‘name’ : ‘foobar’}, {$set : {‘age’ : 36}})

根据条件更新

MySQL:

UPDATE user SET age = age + 3 WHERE name = ‘foobar’

Mongo:

db.user.update({‘name’ : ‘foobar’}, {$inc : {‘age’ : 3}})

聚合计算

aggregate

aggregete实例

查询满足下面集合中满足 gzh 与 channelId条件并对userNum求和。

{_id:"1",gzh:"abc",channelId:"1","date":"2017-8-01","userNum":1232} {_id:"1",gzh:"abc",channelId:"2","date":"2017-8-02","userNum":1232} {_id:"1",gzh:"abc",channelId:"3","date":"2017-8-03","userNum":1632} {_id:"1",gzh:"abc",channelId:"4","date":"2017-8-04","userNum":132} {_id:"1",gzh:"abc",channelId:"5","date":"2017-8-05","userNum":232} {_id:"1",gzh:"abc",channelId:"6","date":"2017-8-06","userNum":123} {_id:"1",gzh:"abc",channelId:"1","date":"2017-7-01","userNum":132} {_id:"1",gzh:"abc",channelId:"2","date":"2017-7-02","userNum":162} {_id:"1",gzh:"abc",channelId:"3","date":"2017-7-03","userNum":232} {_id:"1",gzh:"abc",channelId:"4","date":"2017-7-04","userNum":432} {_id:"1",gzh:"abc",channelId:"5","date":"2017-7-05","userNum":232} {_id:"1",gzh:"abc",channelId:"6","date":"2017-7-06","userNum":12} db.cllection.aggregate([ { $match : { gzh:"abc",channelId:"123"} }, { $group : { _id:"channelId", userSum:{$sum:'$userNum'} } } ]);

MapReduce

mapReduce实例

根据gzh与channeId 添加下userNum的和。 其中channelId 可以是给定的任意多个。给出的collection的item如下：

{_id:"1",gzh:"abc",channelId:"1","date":"2017-8-01","userNum":1232} {_id:"1",gzh:"abc",channelId:"2","date":"2017-8-02","userNum":1232} {_id:"1",gzh:"abc",channelId:"3","date":"2017-8-03","userNum":1632} {_id:"1",gzh:"abc",channelId:"4","date":"2017-8-04","userNum":132} {_id:"1",gzh:"abc",channelId:"5","date":"2017-8-05","userNum":232} {_id:"1",gzh:"abc",channelId:"6","date":"2017-8-06","userNum":123} {_id:"1",gzh:"abc",channelId:"1","date":"2017-7-01","userNum":132} {_id:"1",gzh:"abc",channelId:"2","date":"2017-7-02","userNum":162} {_id:"1",gzh:"abc",channelId:"3","date":"2017-7-03","userNum":232} {_id:"1",gzh:"abc",channelId:"4","date":"2017-7-04","userNum":432} {_id:"1",gzh:"abc",channelId:"5","date":"2017-7-05","userNum":232} {_id:"1",gzh:"abc",channelId:"6","date":"2017-7-06","userNum":12}

根据上面给出的集合，我们可以下如下的mapreduce来进行计算。

db.collection.mapReduce( function() { var channelIds = ["1", "2", "3", ]; if(channelIds.indexOf(this.channelId) >= 0) { emit( this.gzh,this.userNum); } }, function(key, values) { var sum = 0; for(var i = 0; i < values.length; i++) { sum = sum + values[i]; } return sum; }, { query:{gzh:"abc"}, out:"order_totals", finalize:function(key, reducedVal) { print(reducedVal) return reducedVal; } } ).find();

最后运行输入：

{ “_id” : “abc”, “value” : xxxx }

详情请参考官网文档

mongodb指导手册