In a universal relation view queries are expressed without mentioning relation names and they are evaluated by using socalled window functions.We discuss several design rules for database schemes suited for universal relation views and formalize one of them, the One Flavor Assumption.Intuitively the One Flavor Assumption says that the real world significance of any tuple of a window does not depend on the details of its construction.For its formalization we define the essence of join paths which are used in the universal relation system DURST.We prove a deep connection between database schemes satisfying the One Flavor Assumption and y-acyclic schemes.For such database schemes we carefully compare the essence of join paths with the unique minimal Do-connection, and the result of the modified GYOreduction.For universal relation views based on such schemes the DURST window functions are essentially optimized.