An 800 database, or toll-free number database, is a database of U.S. 800 and 888 phone numbers that can be used to direct calls to your business when the customer dials an 800 number or any number with the four-digit prefixes 800, 888, 877, 866 and 855. Most call centers will require their call agents to access the database so that customers can be directed to the appropriate department.