• Fields

• Forms

• Pages

• Text boxes

If you want to force the user to make an entry in this field before saving the record to the database, then use the OnBeforePutRecord Trigger.

You can use this property with the InitValue Property to ensure that an entry is made in this field. This setting is evaluated for controls and fields during validation.

You can set the NotBlank property to Yes on primary fields in a table. Do not set the NotBlank property to Yes on other fields in a table.

Reference