Among the advantages of using a relational database is enforcing business rules. Based on our understanding of how the structure of a relational database helps prevent redundancy and other advantages, how does the primay key/ foreign key relationship stucture help enforce a business rule that indicates that a company shouldnt process any purchase orders from suppliers who dont exist in the database?

Among the advantages of using a relational database is enforcing business rules. Based on our understanding of how the structure of a relational database helps prevent redundancy and other advantages, how does the primay key/ foreign key relationship stucture help enforce a business rule that indicates that a company shouldnt process any purchase orders from suppliers who dont exist in the database