在mongo/mongoose中同时连接多个数据库

npm install mongodb mongoose

const mongoose = require('mongoose');

// 连接数据库1
mongoose.connect('mongodb://localhost/db1', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => console.log('Connected to db1'))
  .catch(err => console.error('Error connecting to db1:', err));

// 连接数据库2
mongoose.connect('mongodb://localhost/db2', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => console.log('Connected to db2'))
  .catch(err => console.error('Error connecting to db2:', err));

const mongoose = require('mongoose');

// 定义模式
const userSchema = new mongoose.Schema({
  name: String,
  age: Number
});

// 创建模型
const User1 = mongoose.model('User1', userSchema, 'collection1');
const User2 = mongoose.model('User2', userSchema, 'collection2');

const User1 = require('./models/User1');
const User2 = require('./models/User2');

// 在数据库1中创建新用户
const user1 = new User1({ name: 'John', age: 25 });
user1.save()
  .then(() => console.log('User1 created:', user1))
  .catch(err => console.error('Error creating User1:', err));

// 在数据库2中创建新用户
const user2 = new User2({ name: 'Jane', age: 30 });
user2.save()
  .then(() => console.log('User2 created:', user2))
  .catch(err => console.error('Error creating User2:', err));