重新学习mongodb:操作mongodb数据库

我就是我 2022-05-04 23:52 313阅读 0赞

**1.启动shell**

**2.数据库、集合、文档**

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**3.插入和查询**

插入：db.users.insert(\{username:"smith"\})

查询：db.users.find()

mongodb的\_id字段：

![70 1][]

传递查询条件：db.users.find(\{username:"smith"\});

db.users.find(\{$and:\[\{\_id:ObjectId("5bc6c836efe8a9eb8c20aba4")\},\{username:"smith"\}\]\})

db.users.find(\{$or:\[\{\_id:ObjectId("5bc6c836efe8a9eb8c20aba4")\},\{username:"smith"\}\]\})

**4.更新文档**

![70 2][]

更新操作符：db.users.update(\{username:"smith"\},\{$set:\{country:"Canada"\}\})

db.users.update(\{country:"Canada"\},\{$set:\{usrname:"smith"\}\})

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替换更新：db.users.update(\{usrname:"smith"\},\{username:"smith"\})

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![70 5][]

db.users.update(\{username:"smith"\},\{$unset:\{country:1\}\})

更新复杂的数据：

db.users.update(  
    \{username:"smith"\},  
    \{  
        $set:\{  
            favorites:\{  
                cities:\["Chicago","Cheyenne"\],  
                movies:\["Casablanca","For a few Dollara More","The String"\]  
            \}  
        \}  
\})

db.users.update(  
    \{username:"jones"\},  
    \{  
        $set:\{  
            favorites:\{  
                movies:\["Casablanca","Rocky"\]  
            \}  
        \}  
\})

![70 6][]

db.users.find(\{"favorites.movies":"Casablanca"\})

高级更新：

![70 7][]

![70 8][]

**5.删除数据**

清空数据：db.foo.remove()

按条件删除：db.foo.remove(\{"favoritest.citys":"Cheyenne"\})

删除集合附带删除索引：db.foo.drop()

**6.shell的其他特性：**

db.help()

mongo --help

**7.使用索引创建和查询**

![70 9][]

for(i=0;i<20000;i++)\{

db.numbers.save(\{num:i\});

7.1范围查找：$gt 和 $lt

db.numbers.find(\{"$and":\[\{num:\{"$gt":1000\}\},\{num:\{"$lt":2000\}\}\]\})

7.2索引和explain()

分析：db.numbers.find(\{num:\{"$gt":19995\}\}).explain("executionStats")

创建索引：db.numbers.createIndex(\{num:1\})

**8:基本管理**

8.1:获取数据库的信息 show dbs

展示所有的集合：show  collections

低级别数据库和集合的分析：db.stats() ,db.numbers.stats()

8.2:命令如何执行：

db.runCommand(\{dastats:1\})

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