Scripting reference qualifiers

Chapter 1, ServiceNow Foundations, looked at reference qualifiers. Reference qualifiers filter the choices available in a referenced field. The three options (simple, dynamic, and advanced) all work in the same way under the hood. They provide an encoded query, which is used by the platform to find the records that can be selected. Scripted reference qualifiers use JavaScript to accomplish this in a Script Include, in two broad ways:

• They dynamically create an encoded query. For example, you may wish to filter out inactive guests if the currently logged-in user is not a system administrator.
• They dynamically create a list of multiple sys_id values, which is used as an encoded query. The function typically uses a more complicated method to obtain a valid list of records, and passes the list to the reference field. Users then pick an entry from this list.

Showing only guests with reservations

Let's improve the reference qualifier on the Guest field in the Check-in...