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db.shutdownServer() #通用
systemctl status mongod.service #適用于apt安裝的

1. 選擇和創(chuàng)建數(shù)據(jù)庫(kù)

數(shù)據(jù)庫(kù)的創(chuàng)建和進(jìn)入數(shù)據(jù)庫(kù)都是一個(gè)命令

use 庫(kù)名

創(chuàng)建一個(gè)數(shù)據(jù)庫(kù)名為articledb

use articledb

注意mongodb的存儲(chǔ)方式，只創(chuàng)建庫(kù)沒有數(shù)據(jù)時(shí)候，這個(gè)時(shí)候數(shù)據(jù)庫(kù)是存在內(nèi)存中，只有數(shù)據(jù)庫(kù)中有內(nèi)容才會(huì)存放到磁盤，所以創(chuàng)建完沒有數(shù)據(jù)的庫(kù)使用show dbs是看不到庫(kù)的。

查看權(quán)限內(nèi)所有的數(shù)據(jù)庫(kù)

show dbs
或者
show databases

查看當(dāng)前正在使用的數(shù)據(jù)庫(kù)

db

有一些數(shù)據(jù)庫(kù)名是保留的，可以直接訪問這些有特殊作用的數(shù)據(jù)庫(kù)

admin: 從權(quán)限的角度來(lái)看，這是"root"數(shù)據(jù)庫(kù)。要是將一個(gè)用戶添加到這個(gè)數(shù)據(jù)庫(kù)，這個(gè)用戶自動(dòng)繼承所有數(shù)據(jù)庫(kù)的權(quán)限。一些特定的服務(wù)器端命令也只能從這個(gè)數(shù)據(jù)庫(kù)運(yùn)行，比如列出所有數(shù)據(jù)庫(kù)或者關(guān)閉服務(wù)器。
local: 這個(gè)數(shù)據(jù)永遠(yuǎn)不會(huì)被復(fù)制，可以用來(lái)存儲(chǔ)限于本地單臺(tái)服務(wù)器的任意集合
config: 當(dāng)mongo用于分片設(shè)置時(shí)，config數(shù)據(jù)庫(kù)在內(nèi)部使用，用于保存分片的相關(guān)信息

2. 數(shù)據(jù)庫(kù)的刪除

db.dropDatabase()

3. 集合操作

3.1 集合的顯式創(chuàng)建

基本語(yǔ)法格式

db.createCollection(集合名稱)

創(chuàng)建一個(gè)名為mycollection的普通集合

db.createCollection(mycollection)

查看當(dāng)前庫(kù)中的集合(表)

show collections
或
show tables

3.2 集合的隱形創(chuàng)建

當(dāng)向一個(gè)集合插入一個(gè)文檔的時(shí)候，如果集合不存在，則自動(dòng)創(chuàng)建集合
具體看文檔插入部分
通常我們使用隱式創(chuàng)建文檔

3.3 刪除集合

基本語(yǔ)法格式

db.集合名.drop()

刪除mycollection集合

db.mycollection.drop()

4. 文檔的基本操作（增刪改查）

4.1 文檔的插入

單個(gè)文檔插入
創(chuàng)建一個(gè)comment的集合，并插入文檔

db.comment.insert({"articleid":"10000","content":"今天天氣真好，陽(yáng)光明媚","userid":"1001","nickname":"Rose","createdatetime":new Date(),"likenum":NumberInt(10),"state":null})

提示：
1）comment集合如果不存在，則會(huì)自動(dòng)創(chuàng)建
2）mongo中的數(shù)字，默認(rèn)情況下是double類型，如果要存整型，必須使用函數(shù)NumberInt(整型數(shù)字)，否則取出來(lái)就有問題了
3）插入當(dāng)前日期使用new Date()
4）插入的數(shù)據(jù)沒有指定_id，會(huì)自動(dòng)生成主鍵值
5）如果某個(gè)字段沒值，可以賦值為null，或者不寫該字段

批量插入
批量插入多條文章評(píng)論：

> db.comment.insertMany([{"articleid":"10001","content":"Are you ok","userid":"1002","nickname":"alonzo","createdatetime":new Date(),"likenum":NumberInt(1000),"state":"1"},
{"articleid":"10001","content":"3q","userid":"1005","nickname":"leijun","createdatetime":new Date(),"likenum":NumberInt(888),"state":"1"},
{"articleid":"10001","content":"very match，陽(yáng)光明媚","userid":"mifans","nickname":"alonzo","createdatetime":new Date(),"likenum":NumberInt(666),"state":"1"},
{"articleid":"10001","content":"hello mifans","userid":"1003","nickname":"zhangsan","createdatetime":new Date(),"likenum":NumberInt(777),"state":"1"},
{"articleid":"10001","content":"base","userid":"1003","nickname":"zhangsan","createdatetime":new Date(),"likenum":NumberInt(777),"state":"1"}])
{
    "acknowledged" : true,
    "insertedIds" : [
        ObjectId("604ac2298b964c15b2b578bd"),
        ObjectId("604ac2298b964c15b2b578be"),
        ObjectId("604ac2298b964c15b2b578bf"),
        ObjectId("604ac2298b964c15b2b578c0"),
        ObjectId("604ac2298b964c15b2b578c1")
    ]
}

學(xué)過(guò)Python應(yīng)該就看出來(lái)，這里實(shí)際就是將多個(gè)字典插入列表里，形成一個(gè)表的多條數(shù)據(jù)

4.2 文檔的查詢

語(yǔ)法

db.文檔名.find()
或
db.文檔名.find({})

> db.comment.find()
{ "_id" : ObjectId("6049d65505bd0c812f09cec6"), "articleid" : "10000", "content" : "今天天氣真好，陽(yáng)光明媚", "userid" : "1001", "nickname" : "Rose", "createdatetime" : ISODate("2021-03-11T08:35:33.041Z"), "likenum" : 10, "state" : null }
{ "_id" : ObjectId("604ac2298b964c15b2b578bd"), "articleid" : "10001", "content" : "Are you ok", "userid" : "1002", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"), "likenum" : 1000, "state" : "1" }
{ "_id" : ObjectId("604ac2298b964c15b2b578be"), "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"), "likenum" : 888, "state" : "1" }
{ "_id" : ObjectId("604ac2298b964c15b2b578bf"), "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "mifans", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"), "likenum" : 666, "state" : "1" }
{ "_id" : ObjectId("604ac2298b964c15b2b578c0"), "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"), "likenum" : 777, "state" : "1" }
{ "_id" : ObjectId("604ac2298b964c15b2b578c1"), "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"), "likenum" : 777, "state" : "1" }

條件查詢，比如查詢articleid為10001的記錄

> db.comment.find({articleid:"10001"})
{ "_id" : ObjectId("604ac2298b964c15b2b578bd"), "articleid" : "10001", "content" : "Are you ok", "userid" : "1002", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"), "likenum" : 1000, "state" : "1" }
{ "_id" : ObjectId("604ac2298b964c15b2b578be"), "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"), "likenum" : 888, "state" : "1" }
{ "_id" : ObjectId("604ac2298b964c15b2b578bf"), "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "mifans", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"), "likenum" : 666, "state" : "1" }
{ "_id" : ObjectId("604ac2298b964c15b2b578c0"), "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"), "likenum" : 777, "state" : "1" }
{ "_id" : ObjectId("604ac2298b964c15b2b578c1"), "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"), "likenum" : 777, "state" : "1" }

如上條件，但只想返回第一條數(shù)據(jù)

> db.comment.findOne({articleid:"10001"})
{
    "_id" : ObjectId("604ac2298b964c15b2b578bd"),
    "articleid" : "10001",
    "content" : "Are you ok",
    "userid" : "1002",
    "nickname" : "alonzo",
    "createdatetime" : ISODate("2021-03-12T01:21:45.418Z"),
    "likenum" : 1000,
    "state" : "1"
}

投影查詢
查詢nickname為alonzo，只顯示userid且不顯示_id：

> db.comment.find({nickname:"alonzo"},{userid:1,_id:0})
{ "userid" : "1002" }
{ "userid" : "mifans" }

查詢結(jié)果只顯示userid、nickname不顯示_id:

> db.comment.find({},{userid:1,nickname:1,_id:0})
{ "userid" : "1001", "nickname" : "Rose" }
{ "userid" : "1002", "nickname" : "alonzo" }
{ "userid" : "1005", "nickname" : "leijun" }
{ "userid" : "mifans", "nickname" : "alonzo" }
{ "userid" : "1003", "nickname" : "zhangsan" }
{ "userid" : "1003", "nickname" : "zhangsan" }

實(shí)際上投影查詢就是查詢表中的列可以理解為db.comment.find({行篩選},{列篩選})
行篩選需要指定具體數(shù)據(jù)，列篩選指定0和1,0為不顯示，1為顯示

由于批量插入數(shù)據(jù)較多容易出現(xiàn)失敗，因此，可以使用try，catch進(jìn)行異常處理，測(cè)試的時(shí)候可以不處理

try {
db.comment.insertMany([{"articleid":"10001","content":"Are you ok","userid":"1002","nickname":"alonzo","createdatetime":new Date(),"likenum":NumberInt(1000),"state":"1"},
{"articleid":"10001","content":"3q","userid":"1005","nickname":"leijun","createdatetime":new Date(),"likenum":NumberInt(888),"state":"1"},
{"articleid":"10001","content":"very match，陽(yáng)光明媚","userid":"mifans","nickname":"alonzo","createdatetime":new Date(),"likenum":NumberInt(666),"state":"1"},
{"articleid":"10001","content":"hello mifans","userid":"1003","nickname":"zhangsan","createdatetime":new Date(),"likenum":NumberInt(777),"state":"1"},
{"articleid":"10001","content":"base","userid":"1003","nickname":"zhangsan","createdatetime":new Date(),"likenum":NumberInt(777),"state":"1"}])
} catch (e) {
    print(e)
}

目前沒怎么理解這個(gè)功能

4.3 文檔的更新

更新文檔的語(yǔ)法：

db.collection.update(query,update,options)

覆蓋的修改
修改userid為1002的記錄，點(diǎn)贊量為1001,輸入以下語(yǔ)句：

> db.comment.update({userid:"1002"},{likenum:NumberInt(1001)})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.comment.find()
{ "_id" : ObjectId("604ad16235ffd35bf6985785"), "likenum" : 1001 }
{ "_id" : ObjectId("604ad16235ffd35bf6985786"), "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 888, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985787"), "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "mifans", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 666, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985788"), "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 777, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985789"), "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 777, "state" : "1" }

可以看到這條更新修改把整個(gè)數(shù)據(jù)都給覆蓋了，重新生成了之前修改的部分

局部修改
為了解決這個(gè)問題，需要使用$set來(lái)實(shí)現(xiàn)，之前添加文檔的時(shí)候細(xì)心的朋友可能發(fā)現(xiàn)有個(gè)userid的值是mifans，這個(gè)是錯(cuò)誤的，現(xiàn)在想把它改為1004，然后nickname改為mifans，命令如下：

> db.comment.update({userid:"mifans"},{$set:{userid:"1004",nickname:"mifans"}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.comment.find({userid:"1004"})
{ "_id" : ObjectId("604ad16235ffd35bf6985787"), "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "1004", "nickname" : "mifans", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 666, "state" : "1" }

批量的修改
更新所有用戶為1003的用戶昵稱為lisi

#默認(rèn)只修改第一條數(shù)據(jù)
> db.comment.update({userid:"1003"},{$set:{nickname:"lisi"}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.comment.find({userid:"1003"})
{ "_id" : ObjectId("604ad16235ffd35bf6985788"), "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "lisi", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 777, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985789"), "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 777, "state" : "1" }
#修改所有符合條件的數(shù)據(jù)（nickname改為lisi2來(lái)做區(qū)分）
> db.comment.update({userid:"1003"},{$set:{nickname:"lisi2"}},{multi:true})
WriteResult({ "nMatched" : 2, "nUpserted" : 0, "nModified" : 2 })
> db.comment.find({userid:"1003"})
{ "_id" : ObjectId("604ad16235ffd35bf6985788"), "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "lisi2", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 777, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985789"), "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "lisi2", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 777, "state" : "1" }

所以只要后面不加參數(shù){multi:true}則只更新第一條數(shù)據(jù)

列值增長(zhǎng)的修改
如果我們想實(shí)現(xiàn)對(duì)某列值在原有值的基礎(chǔ)上的進(jìn)行增加或減少，可以使用$inc運(yùn)算符來(lái)實(shí)現(xiàn)。
下面是對(duì)userid為1003的點(diǎn)贊數(shù)進(jìn)行遞增操作，每次遞增2

> db.comment.find({userid:"1003"})
{ "_id" : ObjectId("604ad16235ffd35bf6985788"), "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "lisi2", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 777, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985789"), "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "lisi2", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 777, "state" : "1" }
> db.comment.update({nickname:"lisi2"},{$inc:{likenum:NumberInt(2)}},{multi:true})
WriteResult({ "nMatched" : 2, "nUpserted" : 0, "nModified" : 2 })
> db.comment.find({nickname:"lisi2"})
{ "_id" : ObjectId("604ad16235ffd35bf6985788"), "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "lisi2", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 779, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985789"), "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "lisi2", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 779, "state" : "1" }

4.4 刪除文檔

刪除文檔的語(yǔ)法結(jié)構(gòu)：

db.集合名稱.remove(條件)

以下語(yǔ)句可以講數(shù)據(jù)全部刪除，請(qǐng)慎用

db.comment.remove({})

如果刪除userid為1003的記錄，輸入以下語(yǔ)句

> db.comment.find()
{ "_id" : ObjectId("604ad16235ffd35bf6985785"), "likenum" : 1001 }
{ "_id" : ObjectId("604ad16235ffd35bf6985786"), "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 888, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985787"), "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "1004", "nickname" : "mifans", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 666, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985788"), "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "lisi2", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 779, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985789"), "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "lisi2", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 779, "state" : "1" }
> db.comment.remove({userid:"1003"})
WriteResult({ "nRemoved" : 2 })
> db.comment.find()
{ "_id" : ObjectId("604ad16235ffd35bf6985785"), "likenum" : 1001 }
{ "_id" : ObjectId("604ad16235ffd35bf6985786"), "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 888, "state" : "1" }
{ "_id" : ObjectId("604ad16235ffd35bf6985787"), "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "1004", "nickname" : "mifans", "createdatetime" : ISODate("2021-03-12T02:26:42.644Z"), "likenum" : 666, "state" : "1" }

刪除comment里的全部數(shù)據(jù)

> db.comment.remove({})
WriteResult({ "nRemoved" : 3 })
> db.comment.find()
>

5. 文檔的分頁(yè)查詢

首先先將上面刪除的數(shù)據(jù)給創(chuàng)建出來(lái)

#創(chuàng)建初始數(shù)據(jù)
try {
db.comment.insertMany([{_id:"1","articleid":"10001","content":"Are you ok","userid":"1002","nickname":"alonzo","createdatetime":new Date(),"likenum":NumberInt(1000),"state":"1"},
{_id:"2","articleid":"10001","content":"3q","userid":"1005","nickname":"leijun","createdatetime":new Date(),"likenum":NumberInt(888),"state":"1"},
{_id:"3","articleid":"10001","content":"very match，陽(yáng)光明媚","userid":"1004","nickname":"mifans","createdatetime":new Date(),"likenum":NumberInt(666),"state":"1"},
{_id:"4","articleid":"10001","content":"hello mifans","userid":"1003","nickname":"zhangsan","createdatetime":new Date(),"likenum":NumberInt(777),"state":"1"},
{_id:"5","articleid":"10001","content":"base","userid":"1003","nickname":"zhangsan","createdatetime":new Date(),"likenum":NumberInt(777),"state":"1"}])
} catch (e) {
    print(e)
}
#查詢一下
> db.comment.find()
{ "_id" : "1", "articleid" : "10001", "content" : "Are you ok", "userid" : "1002", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 1000, "state" : "1" }
{ "_id" : "2", "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 888, "state" : "1" }
{ "_id" : "3", "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "1004", "nickname" : "mifans", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 666, "state" : "1" }
{ "_id" : "4", "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }
{ "_id" : "5", "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }

5.1 統(tǒng)計(jì)查詢

統(tǒng)計(jì)查詢使用count方法,語(yǔ)法如下

db.comment.count(query,option)

例如統(tǒng)計(jì)comment中所有記錄數(shù)：

> db.comment.count()
5

統(tǒng)計(jì)userid為1003的記錄數(shù)

> db.comment.count({userid:"1003"})
2

5.2 分頁(yè)列表查詢

可以使用limit()方法來(lái)讀取指定數(shù)量的數(shù)據(jù)，使用skip()方法來(lái)跳過(guò)指定數(shù)量的數(shù)據(jù)
基本語(yǔ)法如下所示：

db.集合名.find().limit().skip()

返回指定條數(shù)的記錄，可以在find方法后調(diào)用limit來(lái)返回結(jié)果(TopN),默認(rèn)值20，如下查看前三條數(shù)據(jù)：

> db.comment.find().limit(3)
{ "_id" : "1", "articleid" : "10001", "content" : "Are you ok", "userid" : "1002", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 1000, "state" : "1" }
{ "_id" : "2", "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 888, "state" : "1" }
{ "_id" : "3", "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "1004", "nickname" : "mifans", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 666, "state" : "1" }

skip方法同樣接受一個(gè)數(shù)字參數(shù)作為跳過(guò)記錄條數(shù)，即前N個(gè)不要，默認(rèn)值是0，如下查詢時(shí)跳過(guò)前三條數(shù)據(jù)：

> db.comment.find().skip(3)
{ "_id" : "4", "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }
{ "_id" : "5", "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }

分頁(yè)查詢：要求：每頁(yè)兩個(gè)，第二頁(yè)開始：跳過(guò)前兩條數(shù)據(jù)，接著顯示3和4條數(shù)據(jù)，以此類推

#顯示第一頁(yè)，每頁(yè)兩條數(shù)據(jù)
> db.comment.find().skip().limit(2)
{ "_id" : "1", "articleid" : "10001", "content" : "Are you ok", "userid" : "1002", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 1000, "state" : "1" }
{ "_id" : "2", "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 888, "state" : "1" }
#顯示第二頁(yè)，每頁(yè)兩條數(shù)據(jù)
> db.comment.find().skip(2).limit(2)
{ "_id" : "3", "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "1004", "nickname" : "mifans", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 666, "state" : "1" }
{ "_id" : "4", "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }
#顯示第三頁(yè)，每頁(yè)兩條數(shù)據(jù)
> db.comment.find().skip(4).limit(2)
{ "_id" : "5", "articleid" : "10001", "content" : "base", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }

可以看到顯示第三頁(yè)的時(shí)候數(shù)據(jù)不足兩條，則只返回一條

5.3 排序查詢

sort()方法對(duì)數(shù)據(jù)進(jìn)行排序，sort()方法可以通過(guò)參數(shù)指定排序字段，并使用1和-1來(lái)指定排序的方式，其中1為升序排序，-1為降序排序
語(yǔ)法如下：

db.集合名.find().sort({KEY1:1,KEY2:-1})

對(duì)userid升序排序，并對(duì)點(diǎn)贊數(shù)進(jìn)行降序排序

> db.comment.find({},{userid:1,likenum:1}).sort({userid:1,likenum:-1})
{ "_id" : "1", "userid" : "1002", "likenum" : 1000 }
{ "_id" : "4", "userid" : "1003", "likenum" : 777 }
{ "_id" : "5", "userid" : "1003", "likenum" : 777 }
{ "_id" : "3", "userid" : "1004", "likenum" : 666 }
{ "_id" : "2", "userid" : "1005", "likenum" : 888 }

這里數(shù)據(jù)降序看不出來(lái)，理論上userid為1003的那兩個(gè)數(shù)據(jù)likenum會(huì)進(jìn)行降序排列

6. 文檔的更多查詢

6.1正則的復(fù)雜條件查詢

Mongodb的模糊查詢是通過(guò)正則表達(dá)式的方式實(shí)現(xiàn)的，格式為：

db.集合名.find({字段:/正則表達(dá)式/})

提示：正則是js的語(yǔ)法

現(xiàn)在要查詢?cè)u(píng)論內(nèi)容包含“陽(yáng)光明媚”的所有文檔

#因?yàn)樯厦鎰?chuàng)建的文檔只有一條記錄有“陽(yáng)光明媚”，所以再更新其他一條讓它有兩條該數(shù)據(jù)，方便我們查詢
> db.comment.update({_id:"5"},{$set:{content:"base,陽(yáng)光明媚"}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.comment.find({_id:"5"})
{ "_id" : "5", "articleid" : "10001", "content" : "base,陽(yáng)光明媚", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }

#查詢?cè)u(píng)論中包含“陽(yáng)光明媚”的所有文檔
> db.comment.find({content:/陽(yáng)光明媚/})
{ "_id" : "3", "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "1004", "nickname" : "mifans", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 666, "state" : "1" }
{ "_id" : "5", "articleid" : "10001", "content" : "base,陽(yáng)光明媚", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }

查詢以數(shù)字開頭的評(píng)論

> db.comment.find({content:/^[0-9]/})
{ "_id" : "2", "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 888, "state" : "1" }

6.2 比較查詢

<,<=,>,>=這些操作符也是很常用的，格式如下：

db.集合名.find({字段:{$gt:數(shù)值}})  #大于
db.集合名.find({字段:{$lt:數(shù)值}})  #小于
db.集合名.find({字段:{$gte:數(shù)值}})  #大于等于
db.集合名.find({字段:{$lte:數(shù)值}})  #小于等于
db.集合名.find({字段:{$ne:數(shù)值}})  #不等于

查詢?cè)u(píng)論點(diǎn)贊數(shù)大于700的記錄

> db.comment.find({likenum:{$gt:700}})
{ "_id" : "1", "articleid" : "10001", "content" : "Are you ok", "userid" : "1002", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 1000, "state" : "1" }
{ "_id" : "2", "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 888, "state" : "1" }
{ "_id" : "4", "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }
{ "_id" : "5", "articleid" : "10001", "content" : "base,陽(yáng)光明媚", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }

6.3 包含查詢

包含使用$in操作符

查詢?cè)u(píng)論的集合中userid字段包含1003和1004的文檔

> db.comment.find({userid:{$in:["1003","1004"]}})
{ "_id" : "3", "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "1004", "nickname" : "mifans", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 666, "state" : "1" }
{ "_id" : "4", "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }
{ "_id" : "5", "articleid" : "10001", "content" : "base,陽(yáng)光明媚", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }

不包含使用$nin操作符
查詢?cè)u(píng)論集合中userid字段不包含1003和1004的文檔

> db.comment.find({userid:{$nin:["1003","1004"]}})
{ "_id" : "1", "articleid" : "10001", "content" : "Are you ok", "userid" : "1002", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 1000, "state" : "1" }
{ "_id" : "2", "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 888, "state" : "1" }

6.4 條件連接查詢

我們?nèi)绻枰樵兺瑫r(shí)滿足兩個(gè)以上條件，需要使用$and操作符進(jìn)行關(guān)聯(lián)。(相當(dāng)于SQL里的and)
格式為：

db.集合名.find({$and:[{ },{ },{ }]})

查詢?cè)u(píng)論集合中l(wèi)ikenum大于等于700且小于2000的記錄

> db.comment.find({$and:[{likenum:{$gte:NumberInt(700)}},{likenum:{$lt:NumberInt(2000)}}]})
{ "_id" : "1", "articleid" : "10001", "content" : "Are you ok", "userid" : "1002", "nickname" : "alonzo", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 1000, "state" : "1" }
{ "_id" : "2", "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 888, "state" : "1" }
{ "_id" : "4", "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }
{ "_id" : "5", "articleid" : "10001", "content" : "base,陽(yáng)光明媚", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }

如果兩個(gè)以上條件之間是或者的關(guān)系，我們使用操作符進(jìn)行關(guān)聯(lián)，與前面and的使用方式相同格式為：

db.集合名.find({$or:[{ },{ },{ }]})

查詢?cè)u(píng)論集合中userid為1003，或者點(diǎn)贊數(shù)小于1000的文檔記錄：

> db.comment.find({$or:[{userid:"1003"},{likenum:{$lt:NumberInt(1000)}}]})
{ "_id" : "2", "articleid" : "10001", "content" : "3q", "userid" : "1005", "nickname" : "leijun", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 888, "state" : "1" }
{ "_id" : "3", "articleid" : "10001", "content" : "very match，陽(yáng)光明媚", "userid" : "1004", "nickname" : "mifans", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 666, "state" : "1" }
{ "_id" : "4", "articleid" : "10001", "content" : "hello mifans", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }
{ "_id" : "5", "articleid" : "10001", "content" : "base,陽(yáng)光明媚", "userid" : "1003", "nickname" : "zhangsan", "createdatetime" : ISODate("2021-03-14T02:39:11.573Z"), "likenum" : 777, "state" : "1" }

7. 常用命令小結(jié)

選擇切換數(shù)據(jù)庫(kù)：use articledb
插入數(shù)據(jù)：db.comment.insert({bson數(shù)據(jù)})
查詢所有數(shù)據(jù)：db.comment.find()
條件查詢數(shù)據(jù)：db.comment.find({條件})
查詢符合條件的第一條記錄：db.comment.findOne({條件})
查詢符合條件的前n條數(shù)據(jù)：db.comment.find.({條件}).limit(n)
查詢第n條數(shù)據(jù)后的數(shù)據(jù)：db.comment.find({條件}).skip(n)
修改數(shù)據(jù)：db.comment.update({條件},{修改后的數(shù)據(jù)})或者db.comment.update({條件},{$set:{修改后的數(shù)據(jù)}})
修改數(shù)據(jù)并自增某字段的值：db.comment.update({條件},{$inc:{自增的字段:步數(shù)}})
刪除數(shù)據(jù)：db.comment.remove({條件})
統(tǒng)計(jì)數(shù)據(jù)：db.comment.count({條件})
模糊查詢：db.comment.find({字段名:/正則表達(dá)式/})
條件比較查詢：db.comment.find({字段名:{$gt:值}})
包含查詢：db.comment.find({字段名:{$in:[值1，值2]}})
條件連接查詢：db.comment.find({$and:[{條件1},{條件2}]})

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mongodb基本命令

mongodb基本命令

1. 選擇和創(chuàng)建數(shù)據(jù)庫(kù)

2. 數(shù)據(jù)庫(kù)的刪除

3. 集合操作

3.1 集合的顯式創(chuàng)建

3.2 集合的隱形創(chuàng)建

3.3 刪除集合

4. 文檔的基本操作（增刪改查）

4.1 文檔的插入

4.2 文檔的查詢

4.3 文檔的更新

4.4 刪除文檔

5. 文檔的分頁(yè)查詢

5.1 統(tǒng)計(jì)查詢

5.2 分頁(yè)列表查詢

5.3 排序查詢

6. 文檔的更多查詢

6.1正則的復(fù)雜條件查詢

6.2 比較查詢

6.3 包含查詢

6.4 條件連接查詢

7. 常用命令小結(jié)

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容

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mongodb基本命令

1. 選擇和創(chuàng)建數(shù)據(jù)庫(kù)

2. 數(shù)據(jù)庫(kù)的刪除

3. 集合操作

3.1 集合的顯式創(chuàng)建

3.2 集合的隱形創(chuàng)建

3.3 刪除集合

4. 文檔的基本操作（增刪改查）

4.1 文檔的插入

4.2 文檔的查詢

4.3 文檔的更新

4.4 刪除文檔

5. 文檔的分頁(yè)查詢

5.1 統(tǒng)計(jì)查詢

5.2 分頁(yè)列表查詢

5.3 排序查詢

6. 文檔的更多查詢

6.1正則的復(fù)雜條件查詢

6.2 比較查詢

6.3 包含查詢

6.4 條件連接查詢

7. 常用命令小結(jié)

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容

色偷偷精品伊人,欧洲久久精品,欧美综合婷婷骚逼,国产AV主播,国产最新探花在线,九色在线视频一区,伊人大交九欧美,1769亚洲,黄色成人av