Query data in mongodb

Use find (), findOne (), deleteOne () methods to query or delete data in the database

//引入mongoose模块
const mongoose=require("mongoose");
//定义mongodb地址
const url='mongodb://localhost/user';
//连接mongodb
mongoose.connect(url,{useNewUrlParser: true,useUnifiedTopology: true});
//定义Schema
const userSchema=new mongoose.Schema({
	id:{type:Number},
	name:{type:String}
});
var Use=mongoose.model("users",userSchema);
const users=mongoose.model("users");
//查询所有数据
users.find({},function(err,re){
	if(err){	
		console.log(err);
		return false;
	}
	console.log(re);
});
//查询id为2的数据
users.findOne({id:2},function(err,re){
	if(err){	
		console.log(err);
		return false;
	}
	console.log(re);
});
//删除name为张三的数据
users.deleteOne({"name":"张三"},function(err,re){
	if(err){	
		console.log(err);
		return false;
	}
	console.log(re);
});