Retail — grocery store automation
A till that keeps selling when the internet goes down. Sales are written to a local database, and the moment the connection returns, the queued records go up to the server in a single request. The cashier presses nothing. No sale is lost.
The till never waits on the network. Catalogue search, barcode lookup and closing a sale all work offline, and a missing connection is not treated as an error state. When the line comes back, the queued sales go up in one batch and the queue clears itself.
The barcode is scanned, the product and its price come from the local catalogue, payment is taken, a receipt number is issued and the sale closes. The sale, its lines, its payment and its outbound record are written in a single transaction, so there is no such thing as a half-finished sale.
Catalogue, pricing and sales reports live on the server, and tills pull the catalogue from it. Change a price centrally and it reaches the till on its own — no transfer service running between two programs.
The installer is downloaded from the web, so no technician visit is needed, and later versions arrive on their own. Each store’s data is separated at the database level rather than left to the care of application code.