These two variables are used to hide fields from the selection bar. Whenever a field starts or ends with the character set in these two user-defined variables, the fields will be hidden the same way as the system fields are. If values are selected in these fields, they won't be shown in the selection bar. However, they can still be used when creating front-end expressions.

The following block of code shows an example of how to set these variables:

SET HidePrefix = '%';
SET HideSuffix = '_';

In this example, all the fields in our model that start with the character % will be hidden. This is a great example of when we work with our table keys. Table keys are usually used to join tables, however, they are hardly used in the front-end and thus I recommend to hide them by setting the HidePrefix variable.

Also, in this example, all fields finishing with _ will be hidden and treated as a system field.

Other scenarios where I recommend you hide fields are when creating data islands with field values using toggle-like functions, such as a language or currency selector. We will most probably want these fields to be clickable in the front-end, yet, we do not necessarily want them to show in the selection bar.