6、更新文档

const mongoose=require('mongoose')

mongoose.connect("mongodb://localhost/playground",{ useNewUrlParser: true,useUnifiedTopology: true})
.then(()=>{console.log("数据库连接成功")})
.catch(err=>{console.log(err,'数据库失败')})

const courseSchema= new mongoose.Schema({
    name:String,
    author:String,
    isPublished:Boolean
});
//使用规则创建集合，参数1是集合名，2是规则
const Course= mongoose.model("Course",courseSchema)
//更新一个，前为条件，后为值,若要更新一大堆数据，只更新第一个
Course.updateOne({name:'javascript'},{name:'java'}).then(res=>{console.log(res)})
//更新多个
Course.updateMany({},{isPublished:true}).then(res=>{console.log(res)})