VIFRED also allows you to set up validation of entered values in a Form, and to add validation error messages. This includes the prohibition of NULL values for key fields. Remember the standard QBF facility allows any data that does not conflict with the data type to be entered.
Once you have created your customised screens using VIFRED, they are saved in the FORMS Catalog which may be accessed from within QBF via QBFnames option on the QBF Start-Up screen. (NOTE: they can also be accessed within the FORMS utility as well). The VIFRED facility is explained in detail in "Ingres Thru Forms & Menus" Part 2 chapters 18 - 22.
VIFRED exercise - do this now.
Continue with this trainer.