Each title can have multiple formats. eg. eBook, Paperback, Hardcover, Bath-book, etc.. The Primary format is the format which gets chosen to appear in searches. It gets chosen based on either client specific business rules or a default rule set.
The default rules
First, we get all the formats for a title based on the product title id and order them by publication date. We then prioritize the formats.Paperback and Hardcover go first followed by eBooks and we end with all the other formats. We only go through published books for this first round.The most recently published Paperback will become the primary format if both an eBook and Paperback version get published at the same time. If there are no published books available we pick the next one that is going to be published.
Client specific business rules
We can amend the default rules and customize them to fit your specific business rules. For example, we can make certain formats more important or have different rules for certain imprints.