节点JS文件内的Firebase实时数据库中的调用函数时，如何更改数据库的引用

Question

我们尝试发送通知取决于将数据添加到firebase实时数据库中的一个集合中，但是我们有多个数据库，我们引用了该数据库，但是看着db仍然引用了默认数据库，我们可以在代码中进行更改：

const functions = require('firebase-functions');
const admin = require('firebase-admin');
var serviceAccount = require("./newkey.json");



admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  databaseURL: "https://....." //link of db here
});

ref = admin.database().ref();

exports.pushNotification = functions.database.ref('/Message   /{pushId}').onWrite( event => { 
 //the problem is here this function still listening to the default databse although after put the link of needed database above in databaseURL
console.log('Push notification event triggered');
var valueObject = event.data.val();
const payload = {
    notification: {
        title: valueObject.title,
        body: valueObject.message,
        sound: "default"
    },
    data: {
        title: valueObject.title,
        message: valueObject.message
    }
};
const options = {
    priority: "high",
    timeToLive: 60 * 60 * 24 //24 hours
};
return admin.messaging().sendToTopic("notifications", payload, options);
});