Features of Good Relational Designs Suppose we combine instructorand department into in_dep,which represents the natural join on the relations instructor and department ID name salary dept name building budget 22222 Einstein 95000 Physics Watson 70000 12121 Wu 90000 Finance Painter 120000 32343 El Said 60000 History Painter 50000 45565 Katz 75000 Comp.Sci. Taylor 100000 98345 Kim 80000 Elec.Eng. Taylor 85000 76766 Crick 72000 Biology Watson 90000 10101 Srinivasan 65000 Comp.Sci. Taylor 100000 58583 Califieri 62000 History Painter 50000 83821 Brandt 92000 Comp.Sci. Taylor 100000 15151 Mozart 40000 Music Packard 80000 33456 Gold 87000 Physics Watson 70000 76543 Singh 80000 Finance Painter 120000 There is repetition of information Need to use null values(if we add a new department with no instructors) Database System Concepts-7th Edition 7.4 @Silberschatz,Korth and SudarshanDatabase System Concepts - 7 7.4 ©Silberschatz, Korth and Sudarshan th Edition Features of Good Relational Designs ▪ Suppose we combine instructor and department into in_dep, which represents the natural join on the relations instructor and department ▪ There is repetition of information ▪ Need to use null values (if we add a new department with no instructors)