mongoose模块化、预定义修饰符（trim、lowercase、uppercase、set）及索引

傷城~ 2021-07-25 18:45 337阅读 0赞

# 一、模块化  #

目录结构如下所示：

![20210301144338130.png][]

**db.js** ：用来连接数据库

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70][]

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！")
    })
    
    module.exports = mongoose;

users.js 表

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 1][]

var mongoose=require("./db.js")
    
    var SchemaUser = mongoose.Schema({
        name: String,
        age: Number,
        status: {
            type: Number,
            default:0
        }
    })
    
    module.exports=mongoose.model('User',SchemaUser,'users')

main.js 入口

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 2][]

let ModelUser = require('./model/users')
    
    ModelUser.find({}, function (err, doc) {
        if (err) {
            console.log(err)
            return
        }
        console.log(doc)
    })

启动

执行命令：**node ./main.js**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 3][]

# 二、预定义修饰符（trim、lowercase、uppercase、set） #

users.js

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 4][]

var mongoose=require("./db.js")
    
    var SchemaUser = mongoose.Schema({
        name: {
            type: String,
            trim: true,//去掉两边的空格
            lowercase:true,//lowercase：全部小写；uppercase:全部大写
        },
        age: Number,
        status: {
            type: Number,
            default:0
        }
    })
    
    module.exports = mongoose.model('User', SchemaUser, 'users')

main.js

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 5][]

let ModelUser = require('./model/users')
    
    let u = new ModelUser({
        name: '   Hello Lijiang   ',
        age: 22,
    })
     
    u.save(function (err, doc) {
        if (err) {
            console.log(err)
            return
        }
        console.log("成功：",doc)
    })

执行结果如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 6][]

可见，trim设为ture后可以去掉字符串两边的空格；lowercase为全部小写；uppercase为全部大写

接下来测试一下set 修饰符

*  set是数据在存入的时候做处理
 *  get是数据在拿出的时候做处理,一般不用它

users.js

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 7][]

main.js

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 8][]

执行结果如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 9][]

# 三、索引 #

index为true或者1表示正序索引，为-1表示逆序索引

users.js

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 10][]

或者：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 11][]

查询索引：**db.集合名.getIndexes()**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 12][]

删除索引：**db.集合名.dropIndex(\{索引字段名:1\})，如果以下黄线部分是-1，那么这里命令里面也应该填-1**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 13][]

[20210301144338130.png]: /images/20210725/1cc2ec770c3d4c6c9b7e20d0c3990973.png
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