Final answer:
Entering a value that violates a table's validation rule results in a validation message, alerting the user to correct the data before saving. This ensures data integrity and prevents errors in the database.
Step-by-step explanation:
When a value is entered into a table that violates the validation rule, most database management systems, such as Microsoft Access or SQL databases, will trigger a validation message. This message is designed to alert the user that the entered data does not conform to the predefined criteria set for that particular field or table. For example, if a field is intended to only accept dates in the future, and a past date is entered, the validation rule would prevent this from being saved and display a message indicating the error.
The function of these validation rules is to ensure data integrity and to prevent errors that could lead to incorrect or incomplete data. Upon encountering a validation error, the user will generally be required to correct the data before the system allows it to be saved. This proactive approach in data management is crucial for maintaining the quality and reliability of the stored information.