Where can you add validation in Mendix?

Validation in Mendix can be added in multiple areas, and the most comprehensive option encompasses all relevant locations where validations can occur. The Domain Model allows for the definition of constraints on attributes and entities, ensuring that data adheres to specific rules before it is saved. This is crucial for maintaining data integrity and enforcing business logic directly at the data structure level.

Additionally, validations can be implemented in Microflows, where you can create logic to check various conditions before executing specific actions, such as before creating or modifying an object. This feature is particularly useful for implementing complex validation rules that are not simply definable through the Domain Model.

Lastly, Pages also allow for validation through user interface elements where input can be validated before being submitted, providing immediate feedback to users. This feature ensures that the data entered meets certain criteria before it reaches the backend.

Thus, by utilizing the Domain Model, Microflows, and Pages, you can create a robust validation framework that enhances data integrity and user experience throughout the application development process.