Maintaining data synchronization for both online and offline users of a web app like a point of sale software is quite confusing and i hope i could get some ideas on understanding how that could be achieved.
For instance for the point of sale software lets say computer A and B all access the same online database and perform basic CRUD operations.
In case computer B goes offline without syncing data that it was working on with online database and computer A is online and therefore is in sync,how do you reconcile the data from computer B when its now online especially when same table rows are worked on by both computers.
Nanbing
A Clean Coder
I guess the key is that apps are able to track all changes of their data, so either the database keeps logs of every changes or never modify existing data but add a new one, have apps to calculate the final state of data.
I tried PouchDB and CouchDB which most of time are working well except conflicts of data repeatedly occurs.