我正在创建一个连接到MongoDB-Atlas的小程序。我创建了一个连接、一个模式、一个模型并创建了一个文档。但不知何故，我的DB名称是“test”，而Collection名称是“users”，而我没有在代码或Atlas中定义它，这是默认名称吗？以及如何创建/重命名DB和Collection。
代码：

使用者.js

const mongoose = require('mongoose');
const SchemaObj = mongoose.Schema;
const userSchema = new SchemaObj({
    name : {
        type:String,
        require:true

    },
    email : {
        type:String,
        require:true
    },
    password: {
        type:String,
        require:true
    }
});

mongoose.model('User',userSchema);

应用程序.js

const express = require('express');
const app = express();
const rout = express.Router();
const PORT = 8888;
const {connectionString} = require('./Keys');
const mongoose = require('mongoose');

app.use(express.json());
app.use(require('./routes/auth'));

app.get('/',(req,res)=>{
    console.log('succesfully connected');
    res.send('im in!');
});

let server = app.listen(PORT,'0.0.0.0',()=>{
    let FuncPort = server.address().port
    let host = server.address().address
    console.log("Example app listening at http://%s:%s", host, FuncPort)
});

const client = mongoose.connect(connectionString, {
  useNewUrlParser: true,
  useUnifiedTopology: true
});
    
mongoose.connection.on('connected',()=>{
    console.log('connected to mongodb oh hell yea');
});

mongoose.connection.on('error',()=>{
    console.log('error connecting to mongodb oh hell yea');
});

验证js

const mongoose = require('mongoose');
const express = require('express');
const route = express.Router();
require('../moduls/User');
const user = mongoose.model("User");

rout.post('/sign',(req,res)=>{
    const {name,password,email} = req.body;
    if(name && password && email) {
        console.log('you god damn right!');
        res.json("you god damn right in response");
    } else {
        console.log('you are god damn wrong stupid idiot!');
        res.status(422);
        res.json("you are god damn wrong you stupid idiot in response");
    }

    user.findOne({email:email}).then((resolve,reject)=>{
        if(resolve)
            return res.status(422).json("user already exist yo");
        
        const newUser = new user({ name, email, password });
        newUser.save().then(() => {
            res.json('saved user!!!!');
        }).catch(err => {
            console.log("there was a problem saving the user")});
        }).catch(err => {  
            console.log(err);
        })
});
module.exports = route;

顺便问一下，mongoose和MongoDB库之间有什么区别？