... Notes 1024PrefacexixThe Sixth EditionThe production of this sixth edition has been guided by the many comments andsuggestions we received concerning the earlier editions, by our own observationswhile ... notallow needed data to be retrieved in a convenient and efficient manner. Moreresponsive data-retrieval systems are required for general use.•Data isolation. Because data are scattered in various ... associated withit a courseid, title, dept name,andcredits, and may also have have associatedprerequisites.•Instructors are identi ed by their uniqueID. Each instructor has name, asso-ciated...