Online and offline point of sales application

Question

I am going to develop a simple Point of Sales system. Mainly all the data will be stored in a central db (mysql server). All the application are going to be window application. Together each local client will have its db copy that will be SQLite stored locally and all the operation will be based on the local db. So at certain interval there will be updates from the local db sqlite into the central db MySQL.

 

window application in c# 

 

How I can implement it.