The XREF, or cross reference table, is a database table that links records together. These tables are very good for normalization in your database. I almost always use an xref when I need an many to many relationship. Usually XREF tables have only two columns with no Primary Key. That's right, the two columns together make them unique. They are both Foreign Keys to other tables. A real life example of this would be in any standard CRM. Let's go over this example right now. Many CRM's could have a table to store...