Consider a multi-layered application where Entity Framework is used. How would you design the validation logic to ensure consistency across layers?

In a multi-layered application, it's essential to enforce data consistency across layers. Implementing validation at the business logic layer ensures that all data manipulation goes through a central point where validation rules can be enforced uniformly. This approach also promotes code reuse and ensures that validation logic is not bypassed by direct access to the data access layer or presentation layer. Entity Framework's built-in validation attributes offer a convenient way to define validation rules directly within the data model, facilitating consistency and maintainability.