Node.js和MySQL-JavaScript应用程序-如何与离线和在线数据库进行交互

Question

I am making a web-app using JavaScript. I plan to use Node.js to connect the app to an existing MySQL database.

First of all, will the Node code be written in the same .js file as my application? Or is it a separate file?

I need the data to be current at all times (even if you were to close the browser and re-open it, AND even in the event of the user not having a wifi connection), so my thought was to constantly update the local device's db and then to intermittently update the MySQL db. Is this the best strategy? If so, how exactly can Node talk to the offline db and MySQL?

Answer 1

First of all, will the Node code be written in the same .js file as my application? Or is it a separate file?

It is possible to keep your client side JavaScript in the same file as your server side JavaScript, but it doesn't make any sense to do so. They are separate programs. (Library files, on the other hand, are a different story).

so my thought was to constantly update the local device's db and then to intermittently update the MySQL db.

Working with a local database and syncing to a shared one is a common strategy. You do need to handle conflicting updates in a way that is sensible for your purposes though.

If so, how exactly can Node talk to the offline db and MySQL?

Node.js can't talk to the offline database, at least not directly.

You will have a web application running in the browser. It will use client side JavaScript with a client side database and some means of communicating with the server (often this is done by sending JSON over HTTP to and from a web service).

Then you will have a server side application running in Node.js. It will use server side JavaScript with a server side MySQL database and some means of communicating with the client (ie an HTTP server hosting a web service).