当前位置: 开发笔记 > 编程语言 > 正文

一口(很长的)气掌握mongodb基本操作

作者：Aerotic | 来源：互联网 | 2023-09-15 09:55

nosql介绍nosql，全称是notonlysql,即“不仅于sql”，相较于关系型数据库，nosql更加灵活，无需去维护复杂的数据关系。数据是json格式，更加直观易读。mon

nosql介绍

nosql，全称是 not only sql, 即“不仅于sql”，相较于关系型数据库，nosql更加灵活，无需去维护复杂的数据关系。数据是json格式，更加直观易读。

mongodb是应用最广泛的一种nosql数据库

《一口(很长的)气掌握mongodb基本操作》 mongdb

安装mongodb

以mac为例：

&＃x2601; ~ brew install mongodb

开启服务

&＃x2601; ~ sudo brew services start mongo Password: ==> Successfully started `mongodb` (label: homebrew.mxcl.mongodb)

连续服务

&＃x2601; ~ mongo MongoDB shell version v3.4.2 connecting to: mongodb://127.0.0.1:27017 MongoDB server version: 4.0.2 WARNING: shell and server versions do not match Server has startup warnings: 2018-09-08T10:56:57.451+0800 I CONTROL [initandlisten] 2018-09-08T10:56:57.451+0800 I CONTROL [initandlisten] ** WARNING: Access control is not enabled for the database. 2018-09-08T10:56:57.451+0800 I CONTROL [initandlisten] ** Read and write access to data and configuration is unrestricted. 2018-09-08T10:56:57.451+0800 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended. 2018-09-08T10:56:57.451+0800 I CONTROL [initandlisten]

配置文件

&＃x2601; mysite cat /usr/local/etc/mongod.conf systemLog: destination: file path: /usr/local/var/log/mongodb/mongo.log logAppend: true storage: dbPath: /usr/local/var/mongodb net: bindIp: 127.0.0.1库操作

查看所有库

> show dbs; admin 0.000GB config 0.000GB local 0.000GB

使用库

> use test; # 如果库不存在，会自动创建该库 switched to db test > show dbs; # 新建的库没有数据，是不会显示在库列表中的 admin 0.000GB config 0.000GB local 0.000GB

删除库

> use test switched to db test > db.dropDatabase() { "ok" : 1 }集合操作

创建集合

> db.createCollection('col1') { "ok" : 1 }

显示集合

> show collections; col1

删除集合

> db.col1.drop() true文档操作

插入文档

> db.col.insert({ # 创建文档时，如果集合不存在，会自动创建集合 ... 'name': '郭靖', ... 'gender': true, ... 'age': 20 ... }); WriteResult({ "nInserted" : 1 })

查询文档

> db.col.find() # 查出所有文档 { "_id" : ObjectId("5b933ce95032d051d0771953") } { "_id" : ObjectId("5b933ced5032d051d0771954") } { "_id" : ObjectId("5b933d1f565bbd5e857dbd89"), "name" : "郭靖", "gender" : true, "age" : 20 } > db.col.find({name: '郭靖'}) # 根据条件筛选文档 { "_id" : ObjectId("5b933d1f565bbd5e857dbd89"), "name" : "郭靖", "gender" : true, "age" : 20 }

更新文档

> db.col.update({'name': '郭靖'}, {$set: {'age': 25}}) WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 }) > db.col.find({name: '郭靖'}) { "_id" : ObjectId("5b933d1f565bbd5e857dbd89"), "name" : "郭靖", "gender" : true, "age" : 25 }

删除文档

> db.col.remove({'name': '郭靖'}) WriteResult({ "nRemoved" : 1 })数据类型

名称	释义
Object ID	文档ID
String	字符串，最常用，必须是有效的UTF-8
Boolean	存储一个布尔值，true或false
Integer	整数可以是32位或64位，这取决于服务器
Double	存储浮点值
Arrays	数组或列表，多个值存储到一个键
Object	用于嵌入式的文档，即一个值为一个文档
Null	存储Null值
Timestamp	时间戳
Date	存储当前日期或时间的UNIX时间格式

object id 每个文档都有一个属性，为_id，保证每个文档的唯一性, objectID是一个12字节的十六进制数
前4个字节为当前时间戳
接下来3个字节的机器ID
接下来的2个字节中MongoDB的服务进程id
最后3个字节是简单的增量值

查询进阶

数据初始化

let data = [ {'name':'郭靖', 'age':20, 'skill':'降龙十八掌', 'gender':true}, {'name':'黄蓉', 'age':18, 'skill':'桃花岛武功', 'gender':false}, {'name':'黄药师', 'age':58, 'skill':'碧海潮生曲', 'gender':true}, {'name':'一灯大师', 'age':60, 'skill':'一阳指', 'gender':true}, {'name':'小龙女', 'age':25, 'skill':'玉女心经', 'gender':false}, {'name':'李莫愁', 'age':30, 'skill':'赤练神掌', 'gender':false}, {'name':'乔峰', 'age':35, 'skill':'降龙十八掌', 'gender':true}, {'name':'王语嫣', 'age':22, 'skill':'懂得各派武功', 'gender':false}, ] for (i in data) { data[i] db.person.insert(data[i]) }

findOne

> db.person.findOne(); // 只查询一条 { "_id" : ObjectId("5b9363badfee996b08be20af"), "name" : "郭靖", "age" : 20, "skill" : "降龙十八掌", "gender" : true } > db.person.findOne({'name': '小龙女'}); { "_id" : ObjectId("5b9363badfee996b08be20b3"), "name" : "小龙女", "age" : 25, "skill" : "玉女心经", "gender" : false }

比较运算

> db.person.find({age: {$gt: 50}}) // 大于 { "_id" : ObjectId("5b9363badfee996b08be20b1"), "name" : "黄药师", "age" : 58, "skill" : "碧海潮生曲", "gender" : true } { "_id" : ObjectId("5b9363badfee996b08be20b2"), "name" : "一灯大师", "age" : 60, "skill" : "一阳指", "gender" : true } > db.person.find({age: {$gte: 60}}) // 大于等于 { "_id" : ObjectId("5b9363badfee996b08be20b2"), "name" : "一灯大师", "age" : 60, "skill" : "一阳指", "gender" : true } > db.person.find({age: {$lt: 20}}) // 小于 { "_id" : ObjectId("5b9363badfee996b08be20b0"), "name" : "黄蓉", "age" : 18, "skill" : "桃花岛武功", "gender" : false } > db.person.find({age: {$lte: 20}}) // 小于等于 { "_id" : ObjectId("5b9363badfee996b08be20af"), "name" : "郭靖", "age" : 20, "skill" : "降龙十八掌", "gender" : true } { "_id" : ObjectId("5b9363badfee996b08be20b0"), "name" : "黄蓉", "age" : 18, "skill" : "桃花岛武功", "gender" : false }

逻辑运算

> db.person.find({$or:[{name:'郭靖'}, {age: {$gt: 50}}]}) // or查询 { "_id" : ObjectId("5b9363badfee996b08be20af"), "name" : "郭靖", "age" : 20, "skill" : "降龙十八掌", "gender" : true } { "_id" : ObjectId("5b9363badfee996b08be20b1"), "name" : "黄药师", "age" : 58, "skill" : "碧海潮生曲", "gender" : true } { "_id" : ObjectId("5b9363badfee996b08be20b2"), "name" : "一灯大师", "age" : 60, "skill" : "一阳指", "gender" : true } > db.person.find({age: {$in: [18, 20]}}) // in查询 { "_id" : ObjectId("5b9363badfee996b08be20af"), "name" : "郭靖", "age" : 20, "skill" : "降龙十八掌", "gender" : true } { "_id" : ObjectId("5b9363badfee996b08be20b0"), "name" : "黄蓉", "age" : 18, "skill" : "桃花岛武功", "gender" : false }

正则查询

> db.person.find({name: /^小/}) { "_id" : ObjectId("5b9363badfee996b08be20b3"), "name" : "小龙女", "age" : 25, "skill" : "玉女心经", "gender" : false }

js函数查询

> db.person.find({$where:function(){return this.age>40}}) { "_id" : ObjectId("5b9363badfee996b08be20b1"), "name" : "黄药师", "age" : 58, "skill" : "碧海潮生曲", "gender" : true } { "_id" : ObjectId("5b9363badfee996b08be20b2"), "name" : "一灯大师", "age" : 60, "skill" : "一阳指", "gender" : true } > db.person.find({$where:function(){return this.skill.indexOf('掌')>=0}}) { "_id" : ObjectId("5b9363badfee996b08be20af"), "name" : "郭靖", "age" : 20, "skill" : "降龙十八掌", "gender" : true } { "_id" : ObjectId("5b9363badfee996b08be20b4"), "name" : "李莫愁", "age" : 30, "skill" : "赤练神掌", "gender" : false } { "_id" : ObjectId("5b9363badfee996b08be20b5"), "name" : "乔峰", "age" : 35, "skill" : "降龙十八掌", "gender" : true }

skip与limit

> db.person.find().skip(1).limit(1) { "_id" : ObjectId("5b9363badfee996b08be20b0"), "name" : "黄蓉", "age" : 18, "skill" : "桃花岛武功", "gender" : false } > db.person.find().limit(1).skip(1) { "_id" : ObjectId("5b9363badfee996b08be20b0"), "name" : "黄蓉", "age" : 18, "skill" : "桃花岛武功", "gender" : false }

skip与limit可单独，也可组合使用。虽然在这种查询条件下，两者的顺序不会影响结果。但推荐使用skip().limit()的顺序。因为在聚合查询时两者的顺序不同会导致结果不同。

显示字段

> db.person.find({}, {name: 1}); // 查询条件为空时，也要有{}空json，_id默认是显示的 { "_id" : ObjectId("5b9363badfee996b08be20af"), "name" : "郭靖" } { "_id" : ObjectId("5b9363badfee996b08be20b0"), "name" : "黄蓉" } { "_id" : ObjectId("5b9363badfee996b08be20b1"), "name" : "黄药师" } { "_id" : ObjectId("5b9363badfee996b08be20b2"), "name" : "一灯大师" } { "_id" : ObjectId("5b9363badfee996b08be20b3"), "name" : "小龙女" } { "_id" : ObjectId("5b9363badfee996b08be20b4"), "name" : "李莫愁" } { "_id" : ObjectId("5b9363badfee996b08be20b5"), "name" : "乔峰" } { "_id" : ObjectId("5b9363badfee996b08be20b6"), "name" : "王语嫣" } > db.person.find({}, {name: 1, _id: 0}); // 不显示_id { "name" : "郭靖" } { "name" : "黄蓉" } { "name" : "黄药师" } { "name" : "一灯大师" } { "name" : "小龙女" } { "name" : "李莫愁" } { "name" : "乔峰" } { "name" : "王语嫣" }

sort排序

> db.person.find({}, {_id:0, name:1, age:1}).sort({age: 1}); // 正序 { "name" : "黄蓉", "age" : 18 } { "name" : "郭靖", "age" : 20 } { "name" : "王语嫣", "age" : 22 } { "name" : "小龙女", "age" : 25 } { "name" : "李莫愁", "age" : 30 } { "name" : "乔峰", "age" : 35 } { "name" : "黄药师", "age" : 58 } { "name" : "一灯大师", "age" : 60 } > db.person.find({}, {_id:0, name:1, age:1}).sort({age: -1}); // 倒序 { "name" : "一灯大师", "age" : 60 } { "name" : "黄药师", "age" : 58 } { "name" : "乔峰", "age" : 35 } { "name" : "李莫愁", "age" : 30 } { "name" : "小龙女", "age" : 25 } { "name" : "王语嫣", "age" : 22 } { "name" : "郭靖", "age" : 20 } { "name" : "黄蓉", "age" : 18 }

count统计

> db.person.count() 8 > db.person.count({age: {$gt: 20}}) 6

distinct过滤重复

> db.person.find({age: {$gt: 20}}, {_id:0, gender:1}) { "gender" : true } { "gender" : true } { "gender" : false } { "gender" : false } { "gender" : true } { "gender" : false } > db.person.distinct('gender', {age: {$gt: 20}}) [ true, false ]聚合

$group分组

// 按gender字段进行分组 db.person.aggregate([ {$group:{_id:'$gender'}} ]); { "_id" : false } { "_id" : true } // 分组后再进行求和统计：求各个组的记录条数 db.person.aggregate([ {$group:{_id:'$gender', counter:{$sum: 1}}} ]); { "_id" : false, "counter" : 4 } { "_id" : true, "counter" : 4 } // 指定某个字段求和 db.person.aggregate([ {$group:{_id:'$gender', counter:{$sum: '$age'}}} ]); { "_id" : false, "counter" : 95 } { "_id" : true, "counter" : 173 } // 将分组中指定字段的值归为一个数组 db.person.aggregate([ {$group:{_id:'$gender', counter:{$push: '$name'}}} ]); { "_id" : false, "counter" : [ "黄蓉", "小龙女", "李莫愁", "王语嫣" ] } { "_id" : true, "counter" : [ "郭靖", "黄药师", "一灯大师", "乔峰" ] } // 将分组中包括的文档归为一个数组 db.person.aggregate([ {$group:{_id:'$gender', counter:{$push: '$$ROOT'}}} ]); { "_id" : false, "counter" : [ { "_id" : ObjectId("5b9363badfee996b08be20b0"), "name" : "黄蓉", "age" : 18, "skill" : "桃花岛武功", "gender" : false }, { "_id" : ObjectId("5b9363badfee996b08be20b3"), "name" : "小龙女", "age" : 25, "skill" : "玉女心经", "gender" : false }, { "_id" : ObjectId("5b9363badfee996b08be20b4"), "name" : "李莫愁", "age" : 30, "skill" : "赤练神掌", "gender" : false }, { "_id" : ObjectId("5b9363badfee996b08be20b6"), "name" : "王语嫣", "age" : 22, "skill" : "懂得各派武功", "gender" : false } ] } { "_id" : true, "counter" : [ { "_id" : ObjectId("5b9363badfee996b08be20af"), "name" : "郭靖", "age" : 20, "skill" : "降龙十八掌", "gender" : true }, { "_id" : ObjectId("5b9363badfee996b08be20b1"), "name" : "黄药师", "age" : 58, "skill" : "碧海潮生曲", "gender" : true }, { "_id" : ObjectId("5b9363badfee996b08be20b2"), "name" : "一灯大师", "age" : 60, "skill" : "一阳指", "gender" : true }, { "_id" : ObjectId("5b9363badfee996b08be20b5"), "name" : "乔峰", "age" : 35, "skill" : "降龙十八掌", "gender" : true } ] }

$match匹配

// 匹配age大于20的文档 db.person.aggregate([ {$match: {age:{$gt:20}}}, ]); { "_id" : ObjectId("5b9363badfee996b08be20b1"), "name" : "黄药师", "age" : 58, "skill" : "碧海潮生曲", "gender" : true } { "_id" : ObjectId("5b9363badfee996b08be20b2"), "name" : "一灯大师", "age" : 60, "skill" : "一阳指", "gender" : true } { "_id" : ObjectId("5b9363badfee996b08be20b3"), "name" : "小龙女", "age" : 25, "skill" : "玉女心经", "gender" : false } { "_id" : ObjectId("5b9363badfee996b08be20b4"), "name" : "李莫愁", "age" : 30, "skill" : "赤练神掌", "gender" : false } { "_id" : ObjectId("5b9363badfee996b08be20b5"), "name" : "乔峰", "age" : 35, "skill" : "降龙十八掌", "gender" : true } { "_id" : ObjectId("5b9363badfee996b08be20b6"), "name" : "王语嫣", "age" : 22, "skill" : "懂得各派武功", "gender" : false } // 在匹配的基础上再进行分组统计 db.person.aggregate([ {$match: {age:{$gt:20}}}, {$group: {_id:'$gender', counter:{$sum:1}}} ]); { "_id" : false, "counter" : 3 } { "_id" : true, "counter" : 3 }

$project显示字段

db.person.aggregate([ {$match: {age:{$gt:20}}}, {$group: {_id:'$gender', counter:{$sum:1}}}, {$project: {_id:0, counter:1}} ]); { "counter" : 3 } { "counter" : 3 }

$sort排序

db.person.aggregate([ {$match: {age: {$gt: 20}}}, {$group: {_id: '$gender', counter: {$sum:1}}}, {$project: {counter: 1}}, {$sort: {_id: -1}} ]); { "_id" : true, "counter" : 3 } { "_id" : false, "counter" : 3 }

$《一口(很长的)气掌握mongodb基本操作》$ limit

// skip 和 limit 在聚合时有顺序区分的。开发时养成先skip，再limit的习惯 db.person.aggregate([ {$match: {age: {$gt: 20}}}, {$group: {_id: '$gender', counter: {$sum:1}}}, {$project: {counter: 1}}, {$sort: {_id: -1}}, {$skip: 1}, {$limit: 1} ]); { "_id" : false, "counter" : 3 } db.person.aggregate([ {$match: {age: {$gt: 20}}}, {$group: {_id: '$gender', counter: {$sum:1}}}, {$project: {counter: 1}}, {$sort: {_id: -1}}, {$limit: 1}, {$skip: 1} ]); // 结果为空

$unwind

将文档中的数组解开

db.shirt.insert({_id:1, title:'t-shirt', size:['M', 'L', 'S']}); db.shirt.aggregate([ {$unwind: '$size'} ]); { "_id" : 1, "title" : "t-shirt", "size" : "M" } { "_id" : 1, "title" : "t-shirt", "size" : "L" } { "_id" : 1, "title" : "t-shirt", "size" : "S" } // unwind作用的字段为不同值时的情况 db.shirt.insert({_id: 2, title: 't2', size:[]}); db.shirt.insert({_id: 3, title: 't3'}); db.shirt.insert({_id: 4, title: 't4', size:null}); db.shirt.insert({_id: 5, title: 't5', size:'M'}); // 空值，没有size的数据丢了 db.shirt.aggregate([ {$unwind: '$size'} ]); { "_id" : 1, "title" : "t-shirt", "size" : "M" } { "_id" : 1, "title" : "t-shirt", "size" : "L" } { "_id" : 1, "title" : "t-shirt", "size" : "S" } { "_id" : 5, "title" : "t5", "size" : "M" } // 阻止空值丢失 db.shirt.aggregate([ {$unwind: {path: '$size', preserveNullAndEmptyArrays:true}} ]); { "_id" : 1, "title" : "t-shirt", "size" : "M" } { "_id" : 1, "title" : "t-shirt", "size" : "L" } { "_id" : 1, "title" : "t-shirt", "size" : "S" } { "_id" : 2, "title" : "t2" } { "_id" : 3, "title" : "t3" } { "_id" : 4, "title" : "t4", "size" : null } { "_id" : 5, "title" : "t5", "size" : "M" }索引

创建一个一百万文档的集合

for(i=0; i<1000000; i++){ db.test_index.insert({name:'test'+i, rank:i}); }; WriteResult({ "nInserted" : 1 })

在没有索引的情况下查找数据

db.test_index.find({name: 'test10000'}); { "_id" : ObjectId("5b937532dfee996b08be47c7"), "name" : "test10000", "rank" : 10000 } db.test_index.find({name: 'test10000'}).explain('executionStats'); // executionTimeMillis 值为 416 表示执行 416 毫秒

创建索引

db.test_index.ensureIndex({name: 1}); { "createdCollectionAutomatically" : false, "numIndexesBefore" : 1, "numIndexesAfter" : 2, "ok" : 1 }

再次分析性能

db.test_index.find({name: 'test10000'}).explain('executionStats'); // executionTimeMillis 降为 8 毫秒用户权限管理

创建超级管理员
修改配置文件，启用身份验证
重启服务
使用超级管理员登录
创建普通用户
使用普通用户登录

创建用户

db.createUser({ user:'admin', pwd:'admin123', roles:[{role:'root', db:'admin'}], passwordDigestor: 'server' })

修改配置

security: authorization: enabled

重启服务

sudo brew services restart mongo

直接用mongo登录，无法使用show dbs等命令

&＃x2601; ~ mongo MongoDB shell version v3.4.2 connecting to: mongodb://127.0.0.1:27017 MongoDB server version: 4.0.2 WARNING: shell and server versions do not match > db test > show dbs; 2018-09-08T09:51:53.531+0800 E QUERY [thread1] Error: listDatabases failed:{ "ok" : 0, "errmsg" : "command listDatabases requires authentication", "code" : 13, "codeName" : "Unauthorized" } : _getErrorWithCode@src/mongo/shell/utils.js:25:13 Mongo.prototype.getDBs@src/mongo/shell/mongo.js:62:1 shellHelper.show@src/mongo/shell/utils.js:755:19 shellHelper@src/mongo/shell/utils.js:645:15 @(shellhelp2):1:1

使用超级管理员登录

&＃x2601; ~ mongo -u admin -p --authenticationDatabase admin MongoDB shell version v3.4.2 Enter password: connecting to: mongodb://127.0.0.1:27017 MongoDB server version: 4.0.2 WARNING: shell and server versions do not match Server has startup warnings: 2018-09-08T09:51:35.534+0800 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended. 2018-09-08T09:51:35.534+0800 I CONTROL [initandlisten] > show dbs; admin 0.000GB config 0.000GB local 0.000GB py3 0.004GB

创建普通用户

db.createUser({ user:'py3', pwd:'admin123', roles:[{role:'readWrite', db:'py3'}], passwordDigestor: 'server' })

使用普通管理员登录

&＃x2601; ~ mongo -u py3 -p --authenticationDatabase py3 MongoDB shell version v3.4.2 Enter password: connecting to: mongodb://127.0.0.1:27017 MongoDB server version: 4.0.2 WARNING: shell and server versions do not match > show dbs; py3 0.004GB

普通管理员只能在指定的数据库，无法登录其他数据库

&＃x2601; ~ mongo -u py3 -p --authenticationDatabase admin MongoDB shell version v3.4.2 Enter password: connecting to: mongodb://127.0.0.1:27017 MongoDB server version: 4.0.2 WARNING: shell and server versions do not match 2018-09-08T10:14:02.358+0800 E QUERY [thread1] Error: Authentication failed. : DB.prototype._authOrThrow@src/mongo/shell/db.js:1459:20 @(auth):6:1 @(auth):1:2 exception: login failed