Relational integrity constraint: rule that enforces basic and fundamental information-based constraints e.g. Users cannot create an order for a nonexistent customerAn order cannot be shipped without an addressBusiness-critical integrity constraint: rule that enforce business rules vital to an organization’s success and often require more insight and knowledge than relational integrity constraintse.g. Product returns are not accepted for fresh product 15 days after purchaseA discount maximum of 20 percent