How do you create a validation rule in access?

To create a validation rule in Microsoft Access, open your table in Design View and select the field you want to validate. In the Field Properties pane at the bottom, locate the "Validation Rule" property and enter your desired expression (e.g., >=0 for non-negative numbers). You can also set the "Validation Text" property to provide a custom error message when the rule is violated. Finally, save your changes to enforce the validation rule when data is entered or modified in that field.