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The idea here is that discounts should be both transparent and private -- if you were a large company you might set different discounts on different products so that different trading partners have a unique relationship with you. For instance, bulk sales of textbooks sold to a college bookstores are treated differently than single sales by a trade retail store. Using a code it allows you to support the former and the latter at the same time while acknowledging different products may have a different discount.
A large publisher may have a list as long as 40 or 50 codes – many of which might, for a given retailer who sells single copies, represent an identical discount, while for another partner, a wholesaler or a college bookstore, might have much more complex coding.vary wildly
How do they know? You tell them – likely after negotiation – what it means.
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Most Canadian trade publishers have a single discount code applied to all records and typically have a standard discount for all accounts. The discount coding can be as complex as your business needs require but there's no reason to make it complicated.
Take your most complex business partner – the one with the most variation that needs to be accommodated – and create a code list based on their needs. Then assess other accounts – are there extra variations? Once you have all the codes you need applied to all the prices (remember that prices can be set for consumer sales and a number of institutions like libraries) you apply your code list. Each trading partner gets a defining table.