What are bar codes used for?

What are bar codes used for?
What exactly are they for?
Can it show the date that the item was purchased?
Where it was purchase from?

The reason I am asking is because a company wants to use it as a proof of purchase but I don’t really see what they could tell from it.

Best answer:

en.wikipedia.org/wiki/Barcode#Use

†Christian†

Under Forum

1 Comment for What are bar codes used for?

1. Mathias | December 30th, 2007 at 3:11 pm

Most stored use a set of several numbers to identify items and keep track of the price associated with them. The bar code is just an image that represents the numbers so they can be scanned by an optical receptor for checking the item and its price. A bar code can only hold set data. You cannot change the data i.e. setting purchase dates/locations. Bar codes are just a means of finding archived information.