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一口(很长的)气掌握mongodb基本操作

一口(很长的)气掌握mongodb基本操作

作者: 闲睡猫 | 来源:发表于2018-09-08 15:31 被阅读40次

    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

    mongdb

    安装mongodb

    以mac为例：

    ☁  ~  brew install mongodb

    开启服务

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

    连续服务

    ☁  ~  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

    ☁  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 }

    skip与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

    1. 创建超级管理员
    2. 修改配置文件，启用身份验证
    3. 重启服务
    4. 使用超级管理员登录
    5. 创建普通用户
    6. 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

    ☁  ~  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

    ☁  ~  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

    ☁  ~  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

    ☁  ~  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

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