Mongodb 2

Bertha 。 2021-10-01 04:34 250阅读 0赞

# mongodb使用 #

## 回顾mysql ##

*  所有表的集合 --库
 *  每一组信息 --表
 *  每一条信息 --字段

## 但是在mongodb中 ##

*  作为外层的容器还是叫databses
 *  在mongodb中表这个东西已经不存在了而叫做 集合（collection）
 *  在mongodb中字段这个东西也不存在了而叫做文档（document）

## mongodb使用 ##

*  连接  
    **语法：mongo空格127.0.0.1:27017**

E:\MongoDB\bin>mongo
    MongoDB shell version v3.4.15-35-gae53ff0702
    connecting to: mongodb://127.0.0.1:27017
    MongoDB server version: 3.4.15-35-gae53ff0702
    Server has startup warnings:
    2019-08-13T14:53:41.467+0800 I CONTROL  [initandlisten]
    2019-08-13T14:53:41.467+0800 I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
    2019-08-13T14:53:41.467+0800 I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
    2019-08-13T14:53:41.467+0800 I CONTROL  [initandlisten]

*  操作

1.  查看数据库:show空格dbs;

> show dbs
    admin  0.000GB
    local  0.000GB
    mgd    0.000GB

1.  切换/新增（如果有就是切换 如果没有就是新增)数据库  
    use 空格 要切换或者新增的库

> use mgd
    switched to db mgd

**注意新增有问题**

> show dbs
    admin  0.000GB
    local  0.000GB
    mgd    0.000GB

**当我们输入一个没有的库名的时候本应该是新增 但是当我们输入之后发现并没有新增 原因是（其实新增了只是里面没有集合所以不显示）**

1.  创建集合：  
    **db.要创建的集合名字.insert(\{k:v\})**

> db.chuichui.insert({"name":"大锤",age:20,sex:"男"})
    WriteResult({ "nInserted" : 1 })

1.  查看集合  
    **show空格collections**

> show collections
    chuichui

1.  删除库  
    **必须先切换到你要删的库 use空格库名**  
    **db.dropDatabase()**
2.  删除集合  
    **必须先要切换到指定要删除集合的库中**  
    **db.要删除的集合名.drop()**

> use mgd
    switched to db mgd
    > db.chuichui.drop()
    true
    > show collections
    >

*基本的外围操作完了*

## 上面的内容重要程度没有下面高必须要记住: ##

### 1. 要对集合进行增删改查那么必须要有集合 ###

**只创建集合的语法**  
**db.createCollection(“要创建集合的名字”);**

> db.createCollection("NO13")
    { "ok" : 1 }

### 2. 新增 ###

**最单纯的新增（基础语法）**  
**db.要插入的集合名.insert(\{k:v\})**

> db.NO13.insert({"name":"王大锤",age:20,sex:"男"})
    WriteResult({ "nInserted" : 1 })

**为了查看我们是否新增成功 使用查询语句来查看**  
**db.要查询的集合.find()**

> db.NO13.find()
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }
    { "_id" : ObjectId("5d53b2c308a6149f969e8df4"), "name" : "王木锤", "age" : 16, "sex" : "女" }
    { "_id" : ObjectId("5d53b2e208a6149f969e8df5"), "name" : "王铜锤", "age" : 18, "sex" : "男" }
    { "_id" : ObjectId("5d53b2f308a6149f969e8df6"), "name" : "王金锤", "age" : 19, "sex" : "男" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }

大家会发现id是自动添加的,比较难记  
**手工新增id**  
**db.要插入的集合名.insert(\{ "\_id":1,k:v\})**

> db.NO13.insert({"_id":1,"name":"王小锤",age:13,sex:"男"})
    WriteResult({ "nInserted" : 1 })

**既然是手工指定那么千万不要重名**

### 3. 多条插入 ###

**db.要插入的集合.insert(\[\{k:v\},\{k:v\}\])**

> db.NO13.insert([{"name":"王钢锤"},{"name":"王石锤"}])
    BulkWriteResult({
            "writeErrors" : [ ],
            "writeConcernErrors" : [ ],
            "nInserted" : 2,
            "nUpserted" : 0,
            "nMatched" : 0,
            "nModified" : 0,
            "nRemoved" : 0,
            "upserted" : [ ]
    })

### 4. 查询 ###

1.  按照条件进行查询

**db.要查询的集合名.find(\{k:v\})**

> db.NO13.find({age:18})
    { "_id" : ObjectId("5d53b2e208a6149f969e8df5"), "name" : "王铜锤", "age" : 18, "sex" : "男" }

1.  格式化查询数据  
    **Db.要查询的数据find(\{k:v\},\{k:0/1\}) 0不显示 1显示**

> db.NO13.find({"name":"王金锤"},{"age":1,"_id":0})
    { "age" : 19 }
    > db.NO13.find({"age":20},{"sex":1,"_id":0})
    { "sex" : "男" }

1.  查询匹配更多内容  
    **Db.要查询的数据.find(\{查询的内容1，查询的内容2···\})**

> db.NO13.find({"name":"王银锤",sex:"女"})
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }

1.  条件查询  
    **Db.查询的集合.find(\{“要查询的k”:\{条件:值\}\})**  
    **条件**

*  (>) 大于 - $gt
 *  (<) 小于 - $lt
 *  (>=) 大于等于 - $gte
 *  (<= ) 小于等于 - $lte
 *  (!=) 不等于 - $ne:  
    **代码：**

> db.NO13.find({"age":{$gt:19}})
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }
    > db.NO13.find({"age":{$lt:19}})
    { "_id" : ObjectId("5d53b2c308a6149f969e8df4"), "name" : "王木锤", "age" : 16, "sex" : "女" }
    { "_id" : ObjectId("5d53b2e208a6149f969e8df5"), "name" : "王铜锤", "age" : 18, "sex" : "男" }
    { "_id" : 1, "name" : "王小锤", "age" : 13, "sex" : "男" }
    > db.NO13.find({"age":{$gte:19}})
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }
    { "_id" : ObjectId("5d53b2f308a6149f969e8df6"), "name" : "王金锤", "age" : 19, "sex" : "男" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }
    > db.NO13.find({"age":{$lte:19}})
    { "_id" : ObjectId("5d53b2c308a6149f969e8df4"), "name" : "王木锤", "age" : 16, "sex" : "女" }
    { "_id" : ObjectId("5d53b2e208a6149f969e8df5"), "name" : "王铜锤", "age" : 18, "sex" : "男" }
    { "_id" : ObjectId("5d53b2f308a6149f969e8df6"), "name" : "王金锤", "age" : 19, "sex" : "男" }
    { "_id" : 1, "name" : "王小锤", "age" : 13, "sex" : "男" }
    > db.NO13.find({"age":{$ne:19}})
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }
    { "_id" : ObjectId("5d53b2c308a6149f969e8df4"), "name" : "王木锤", "age" : 16, "sex" : "女" }
    { "_id" : ObjectId("5d53b2e208a6149f969e8df5"), "name" : "王铜锤", "age" : 18, "sex" : "男" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }
    { "_id" : 1, "name" : "王小锤", "age" : 13, "sex" : "男" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df8"), "name" : "王钢锤" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df9"), "name" : "王石锤" }

1.  匹配查询多个内容  
    **Db.要查询的集合.find(\{ $or:\[\{查询的内容1\},\{查询的内容2\}\]\})**

> db.NO13.find({$or:[{"name":"王金锤"},{"name":"王铁锤"}]})
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }
    { "_id" : ObjectId("5d53b2f308a6149f969e8df6"), "name" : "王金锤", "age" : 19, "sex" : "男" }

1.  排序查询  
    **db.要查询的集合.find().sort(\{要排序的内容:-1倒序/1正序\})**

> db.NO13.find().sort({"age":-1})
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b2f308a6149f969e8df6"), "name" : "王金锤", "age" : 19, "sex" : "男" }
    { "_id" : ObjectId("5d53b2e208a6149f969e8df5"), "name" : "王铜锤", "age" : 18, "sex" : "男" }
    { "_id" : ObjectId("5d53b2c308a6149f969e8df4"), "name" : "王木锤", "age" : 16, "sex" : "女" }
    { "_id" : 1, "name" : "王小锤", "age" : 13, "sex" : "男" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df8"), "name" : "王钢锤" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df9"), "name" : "王石锤" }
    
    > db.NO13.find().sort({"age":1})
    { "_id" : ObjectId("5d53b53b08a6149f969e8df8"), "name" : "王钢锤" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df9"), "name" : "王石锤" }
    { "_id" : 1, "name" : "王小锤", "age" : 13, "sex" : "男" }
    { "_id" : ObjectId("5d53b2c308a6149f969e8df4"), "name" : "王木锤", "age" : 16, "sex" : "女" }
    { "_id" : ObjectId("5d53b2e208a6149f969e8df5"), "name" : "王铜锤", "age" : 18, "sex" : "男" }
    { "_id" : ObjectId("5d53b2f308a6149f969e8df6"), "name" : "王金锤", "age" : 19, "sex" : "男" }
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }

**limit读取指定数量的数据记录条数**  
**skip使用skip()方法来跳过指定数量的数据**

> db.NO13.find().skip(4)
    { "_id" : ObjectId("5d53b2f308a6149f969e8df6"), "name" : "王金锤", "age" : 19, "sex" : "男" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }
    { "_id" : 1, "name" : "王小锤", "age" : 13, "sex" : "男" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df8"), "name" : "王钢锤" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df9"), "name" : "王石锤" }
    
    > db.NO13.find().skip(0).limit(2)
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }

**返回结果集中的数量count()**

> db.NO13.find().count()
    9

**修改:**

>db.collection.update(
       {<query>},
       {$set:{<update>}},
       {
         upsert: <boolean>,
         multi: <boolean>
       }
    )

**query:查询出要修改的数据**  
**update:要修改的数据的值**  
**upsert:可选,这个参数的意思是，如果不存在update的记录，是否插入objNew,true为插入，默认是false，不插入**  
**multi: 可选，MongoDB 默认是false,只更新找到的第一条记录，如果这个参数为true,就把按条件查出来多条记录全部更新**  
7. 单纯的修改

> db.NO13.update({"age":16},{"age":116})
    WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
    > db.NO13.find()
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }
    { "_id" : ObjectId("5d53b2c308a6149f969e8df4"), "age" : 116 }
    { "_id" : ObjectId("5d53b2e208a6149f969e8df5"), "name" : "王铜锤", "age" : 18, "sex" : "男" }
    { "_id" : ObjectId("5d53b2f308a6149f969e8df6"), "name" : "王金锤", "age" : 19, "sex" : "男" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }
    { "_id" : 1, "name" : "王小锤", "age" : 13, "sex" : "男" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df8"), "name" : "王钢锤" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df9"), "name" : "王石锤" }
    
    
    > db.NO13.update({"age":116},{$set:{"name":"王家小锤爷"}})
    WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
    > db.NO13.find()
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }
    { "_id" : ObjectId("5d53b2c308a6149f969e8df4"), "age" : 116, "name" : "王家小锤爷" }
    { "_id" : ObjectId("5d53b2e208a6149f969e8df5"), "name" : "王铜锤", "age" : 18, "sex" : "男" }
    { "_id" : ObjectId("5d53b2f308a6149f969e8df6"), "name" : "王金锤", "age" : 19, "sex" : "男" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }
    { "_id" : 1, "name" : "王小锤", "age" : 13, "sex" : "男" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df8"), "name" : "王钢锤" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df9"), "name" : "王石锤" }

**修改更多内容**

> db.NO13.update({"age":19},{$set:{"sec":"半男不女"}},{multi:true})
    WriteResult({ "nMatched" : 2, "nUpserted" : 0, "nModified" : 2 })
    > db.NO13.find()
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }
    { "_id" : ObjectId("5d53b2c308a6149f969e8df4"), "age" : 116, "name" : "王家小锤爷" }
    { "_id" : ObjectId("5d53b2e208a6149f969e8df5"), "age" : 19, "sec" : "半男不女" }
    { "_id" : ObjectId("5d53b2f308a6149f969e8df6"), "name" : "王金锤", "age" : 19, "sex" : "男", "sec" : "半男不女" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }
    { "_id" : 1, "name" : "王小锤", "age" : 13, "sex" : "男" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df8"), "name" : "王钢锤" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df9"), "name" : "王石锤" }

1.  删除  
    **Db.要删除的集合.remove(\{k:v\})默认删除匹配到的所有内容**

> db.NO13.remove({"age":19})
    WriteResult({ "nRemoved" : 2 })
    > db.NO13.find()
    { "_id" : ObjectId("5d53b24708a6149f969e8df2"), "name" : "王大锤", "age" : 20, "sex" : "男" }
    { "_id" : ObjectId("5d53b2a408a6149f969e8df3"), "name" : "王铁锤", "age" : 30, "sex" : "男" }
    { "_id" : ObjectId("5d53b2c308a6149f969e8df4"), "age" : 116, "name" : "王家小锤爷" }
    { "_id" : ObjectId("5d53b30a08a6149f969e8df7"), "name" : "王银锤", "age" : 23, "sex" : "女" }
    { "_id" : 1, "name" : "王小锤", "age" : 13, "sex" : "男" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df8"), "name" : "王钢锤" }
    { "_id" : ObjectId("5d53b53b08a6149f969e8df9"), "name" : "王石锤" }

**只想删除一条 justOne**

### Mongoose是一个node的第三方库,他的作用就是帮助node更好更高效的连接mongodb ###