mongoose入门及基本的增删改查

迈不过友情╰ 2021-07-26 01:17 436阅读 0赞

在test\_mongoose目录下执行以下生成package.json文件

npm init --yes

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70][]

并在当前目录下安装mongoose，执行命令：

npm i mongoose -S

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 1][]

然后使用win+R，输入cmd回车，在dos窗口中，【使用命令**mongo**启动数据库】-【新建testdb数据库】-【新建users集合并插入一条记录】，如下所示：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 2][]

接下来在test\_mongoose文件夹中新建js文件：mongooseDemo.js，其内容如下所示：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 3][]

不用管\{useNewUrlParser:true\}是什么意思，反正加上就行。不加的话会有警告信息

const mongoose = require('mongoose')
    
    mongoose.connect("mongodb://127.0.0.1:27017/testdb", {useNewUrlParser:true},function (err) {
        if (err) {
            console.log(err)
            return
        }
        console.log("数据库连接成功！")
    })

在test\_mongoose目录中执行命令：**node ./mongooseDemo.js** 来运行mongooseDemo.js文件，以测试数据库连接是否成功

![20210301141124953.png][]

![20210301140846263.png][]

出现以上界面，就表示数据库连接成功了！

## 查询记录： ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 4][]

const mongoose = require('mongoose')
    
    mongoose.connect("mongodb://127.0.0.1:27017/testdb")
    
    var UserSchema = mongoose.Schema({
        name: String,
        age: Number,
        status:Number
    })
    
    var User = mongoose.model('User', UserSchema)//注意，当这里是两个参数时，默认连接的是users表，而不是User表。连接的是复数。
    
    User.find({}, function (err, doc) {
        if (err) {
            console.log(err)
            return
        }
        console.log(doc)
    })

**注意：var User = mongoose.model('User', UserSchema)中，当这里是两个参数时，默认连接的是users表，而不是User表。如果想指定表，则在第三个参数的位置处添加表名即可，这行代码等价于：var User = mongoose.model('User', UserSchema,'users')**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 5][]

出现以上界面表示数据库连接成功，并且成功查询出了数据！

## 增加记录 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 6][]

const mongoose = require('mongoose')
    
    mongoose.connect("mongodb://127.0.0.1:27017/testdb")
    
    var UserSchema = mongoose.Schema({
        name: String,
        age: Number,
        status:Number
    })
    
    var User = mongoose.model('User', UserSchema,'users')
    
    var u = new User({
        name: '王五',
        age: 22,
        status:0
    })
    
    u.save(function (err, doc) {
        if (err) {
            console.log(err)
            return
        }
        console.log("成功：",doc)
    })

使用命令Ctrl+C退出命令行，并再次运行mongooseDemo.js文件

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 7][]

![20210301112453546.png][]

记录添加成功！

如果希望添加的记录带有默认值，在定义Schema时可使用如下形式：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 8][]

## 更新记录 ##

将**name:"王五"**的记录改为**name:"wangwu"**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 9][]

const mongoose = require('mongoose')
    
    mongoose.connect("mongodb://127.0.0.1:27017/testdb")
    
    var UserSchema = mongoose.Schema({
        name: String,
        age: Number,
        status:Number
    })
    
    var User = mongoose.model('User', UserSchema,'users')
    
    User.updateOne({ name: "王五" }, { name: "wangwu" }, function (err, res) {
        if (err) {
            console.log(err)
            return
        }
        console.log("更新成功：",res)
    })

![20210301112702688.png][]

![20210301112750730.png][]

## 删除记录 ##

删除**name:"zhangsan"**这条记录

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 10][]

const mongoose = require('mongoose')
    
    mongoose.connect("mongodb://127.0.0.1:27017/testdb")
    
    var UserSchema = mongoose.Schema({
        name: String,
        age: Number,
        status:Number
    })
    
    var User = mongoose.model('User', UserSchema,'users')
    
    User.deleteOne({ name: 'zhangsan' }, function (err, res) {
        if (err) {
            console.log(err)
            return
        }
        console.log("删除成功：",res)
    })

![20210301113351845.png][]

![20210301113440492.png][]

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