What must be created to validate a MedCase_Ext entity using validation rules?

Creating a validation rule set is essential for validating an entity like MedCase_Ext because it specifies the conditions under which the data associated with that entity must adhere to certain standards or rules. The validation rule set enables developers to define the logic that checks the values of entity attributes to ensure they meet required criteria.

This is crucial in maintaining data integrity and ensuring that all entries into the system conform to business requirements or rules. It typically involves defining the criteria for validation, such as mandatory fields, formats, and permissible values, which are then enforced whenever data for MedCase_Ext is being processed.

Other options such as an error log, reference set, or input form serve different purposes. An error log would record any validation errors that occur but does not itself validate data. A reference set provides a way to manage a collection of related data elements but does not contain conditions for validation. An input form facilitates user data entry but does not inherently define or enforce validation rules. Thus, the validation rule set is the necessary construct for ensuring that the MedCase_Ext entity is validated effectively.