Database Modeling & Design Fourth Edition- P56: Database technology has evolved rapidly in the three decades since the rise and eventual dominance of relational database systems. While many specialized database systems (object-oriented, spatial, multimedia, etc.) have found substantial user communities in the science and engineering fields, relational systems remain the dominant database technology for business enterprises. | 262 Solutions to Selected Exercises 6. H - AXY 7. M - NZ 8. MN - HPT 9. XY - MNP Step 1 N is extraneous due to M - N in 7 Step 2 eliminate NP from the RHS due to M - NP from 7 8 After Step 3 using the union axiom 1. AC - BDEGH Combining 1 2 and 3 2. AW- B 3. B - ACF 4. H - AXY 5. M - HNPTZ Combining 7 and 8 6. XY - M Step 4 merging 1. AC - BDEFGH B - AC H - A using Rule 1 for AC being a superkey Rule 2 for B being a superkey the definition of 3NF and A being a prime attribute. 3NF only. 2. AW- BG using Rule 1 for AW to be a superkey. BCNF. 3. H - XY XY - M and M - HNPTZ using Rule 1 for H being a superkey after taking H to its closure H - XYMNPTZ using Rule 2 for M being a superkey from M - H and Rule 2 for XY being a superkey from XY - M. BCNF. Note H- AXY is also possible here. Step 5 minimum set of normalized tables Table 1 ABCDEFGH with superkeys AC B 3NF only Table 2 ABGW with superkey AW 3NF and BCNF Table 3 HMNPTXYZ with superkeys H XY M 3NF and BCNF About the Authors Toby Teorey is a professor in the Electrical Engineering and Computer Science Department at the University of Michigan Ann Arbor. He received his . and . degrees in electrical engineering from the University of Arizona Tucson and a . in computer science from the University of Wisconsin Madison. He was chair of the 1981 ACM SIGMOD Conference and program chair of the 1991 Entity-Relationship Conference. Professor Teorey s current research focuses on database design and performance of computing systems. He is a member of the ACM. Sam Lightstone is a Senior Technical Staff Member and Development Manager with IBM s DB2 Universal Database development team. He is the cofounder and leader of DB2 s autonomic computing R D effort. He is also a member of IBM s Autonomic Computing Architecture Board and in 2003 he was elected to the Canadian Technical Excellence Council the Canadian affiliate of the IBM Academy of Technology. His current research includes numerous topics in autonomic computing .
