Mongoose Schema Validations

validations: https://mongoosejs.com/docs/validation.html

instance methods: https://mongoosejs.com/docs/guide.html#methods

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错误信息一大堆，想看有用的信息？

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• Mongoose Schema Validatioins:

定义validation的条件，一旦违反了条件就会出错，require属性，如果没有填该属性，报错；如果添加schema没有预先定义的属性，不会报错，但是会忽略那个新加的属性，不会被保存到数据表中。 

直接运行node product.js

mongo

show dbs

use shopAPP

db.products.find()

product.js

  1 const mongoose = require('mongoose');
  2 mongoose.connect('mongodb://localhost:27017/shopApp', { useNewUrlParser: true, useUnifiedTopology: true }). //shopApp, use shopApp in mongo!!!
  3     .then(() => {
        console.log("CONNECTION OPEN!!!")
    })
    .catch(err => {
        console.log("OH NO ERROR!!!!")
        console.log(err)
    })

const productSchema = new mongoose.Schema({
    name: {
        type: String,
        required: true,
        maxlength: 20
    },
    price: {
        type: Number,
        required: true,
        min: [0, 'Price must be positive ya dodo!']. //如果破坏了0这个规则，就会打印“Price must be positive ya dodo!”这个信息
    },
    onSale: {
        type: Boolean,
        default: false //如果不另外声明，返回默认值false
    },
    categories: [String],
    qty: {
        online: {
            type: Number,
            default: 0
        },
        inStore: {
            type: Number,
            default: 0
        }
    },
    size: {
        type: String,
        enum: ['S', 'M', 'L']
        //size的值只能在S, M, L三个选择中选
    }

});

//用户自己定义的方法， foundProduct.greet(), 这里调用了greet()，所以this代表foundProduct.
productSchema.methods.greet = function () {
    console.log("HELLLO!!! HI!! HOWDY!!! ")
    console.log(`- from ${this.name}`)
}

    //instance method
productSchema.methods.toggleOnSale = function () {
    this.onSale = !this.onSale;//充当一个开关的作用，拨动一下是关，再拨动一下是开
    return this.save();//如果只运行this.save()，it probably takes time, 
    // 怎么解决呢？ return this one, and set await when calling foundProduct.toggleOnSale();
}

// instance method
productSchema.methods.addCategory = function (newCat) {
    this.categories.push(newCat);//更新new category
    return this.save();
}

    //static method
productSchema.statics.fireSale = function () { //static, 针对于整个Model的方法，而不是某一个实例
    return this.updateMany({}, { onSale: true, price: 0 })
}


const Product = mongoose.model('Product', productSchema);  //products document created!!!


const findProduct = async () => {
    const foundProduct = await Product.findOne({ name: 'Mountain Bike' });
    console.log(foundProduct)
    foundProduct.greet()
    await foundProduct.toggleOnSale();
    console.log(foundProduct)//这儿为什么又要显示一次？——foundProduct.toggleOnSale();之后save change了，可以看update的效果
    await foundProduct.addCategory('Outdoors')
    console.log(foundProduct)
}

Product.fireSale().then(res => console.log(res))
//static methods: fireSale并不是针对与某一个实例对象，而是针对整个model： Product，可以用于批量增删改查
//而instance method只是针对于某一个实例对象的操作

findProduct();


const bike = new Product({ name: 'Cycling Jersey', price: 28.50, categories: ['Cycling'], size: 'XS' })
bike.save()
    .then(data => {
        console.log("IT WORKED!")
        console.log(data);
    })
    .catch(err => {
        console.log("OH NO ERROR!")
        console.log(err)
    })

// runValidators: true必须加上，如果你希望更新的时候也遵循之前的规则！！！
Product.findOneAndUpdate({ name: 'Tire Pump' }, { price: 9 }, { new: true, runValidators: true })
    .then(data => {
        console.log("IT WORKED!")
        console.log(data);
    })
    .catch(err => {
        console.log("OH NO ERROR!")
        console.log(err)
    })