When designing the data structure for a hotel, you may want to link a guest's record with the room they have checked in to. It won't be good for business if we don't know who has checked in where! This is exactly what a reference field does; it creates a link between two records, one pointing to another.
When we examined the URL for a particular record, it contained two parts: the table and the
sys_id value of the record. These are the two items needed to reference a record. So when you create a reference field, you need to select which table it should point to. And the contents of the field will be a 32-character string. Sounds familiar? Yep, you will be storing a
sys_id in that field.
Reference fields are one of the most important ...