Guidelines for Presenting Allowed Values
There are two categories of display types; those that allow the end-users to enter data and those that allow them to choose from a set of values.
The second category consists of the following display types: Check Box, Option Buttons, Dropdown List Box, and Slider. You must define the allowed values for each of these types.
Domains to which you have assigned these display types have a numbered list of values. If the column is mandatory, the first item on the list (i.e. the item with the lowest sequence number) will be used as the default value, unless you specify a default value when you define the domain.
Although these allowed values have a special appearance, their validity is checked at the conceptual level, not at the external level. Therefore, you can write constraints that check whether certain combinations of values are allowed. For example, you could write a constraint specifying that if the end-user chooses the first option from an Option Button group, they cannot then choose the third option from another Option Button group.