1. Tuesday, September 21, 1999 90-728 MIS Lecture Notes1 Homework #3 Results Total points 166 Overall grades: –Average 132.8 or 80% –Minimum 0 –Maximum 163 –Standard Deviation 51 Excluding zeros: –Average: 151.7 or 94.8% –Minimum 120 –Maximum 163 –Standard Deviation 8.65

2. Tuesday, September 21, 1999 90-728 MIS Lecture Notes2 Relational Database Development So Far E-R diagrams –Entities: essential data elements –Attributes: data element descriptors –Entity linkage categories: relationships, connectivity, cardinality Relational Database Models –Tables: correspond to entities –Fields: correspond to attributes –Relationships: correspond to business rules, connectivity –Basic queries Relational Database Applications –Data management –Tables –Forms How do we bring it all together in a real-world setting?

3. Tuesday, September 21, 1999 90-728 MIS Lecture Notes3 Health Inspection Problem Extensions - I Inspection event may be represented two ways: –transaction-in-rows –transaction-in-columns Example: vs: INSPECTION INSPECTION_TYPE M 1 INSPLINK M 1 What are the pros and cons of each approach?

4. Tuesday, September 21, 1999 90-728 MIS Lecture Notes4 Health Inspection Problem Extensions- II Permit could be treated as: –attribute of ESTABLISHMENT –separate entity Example: vs: What are the pros and cons of each approach? PERMIT STATUS ESTABLISHMENT has a 1 M (1,1) (0,M) Permit ID ESTABLISHMENT PERMIT has a PERMIT STATUS has a 1 M Permit ID 1 M (1,1) (0,M)

5. Tuesday, September 21, 1999 90-728 MIS Lecture Notes5 Health Inspection Problem Extensions- III INSPECTION and PERMIT (if included as an entity) could be treated as: –one-to-one related with ESTABLISHMENT (snapshot) –many-to-one related with ESTABLISHMENT (life cycle) What are the pros and cons of each approach?

6. Tuesday, September 21, 1999 90-728 MIS Lecture Notes6 School Bus Garage E-R Diagram

7. Tuesday, September 21, 1999 90-728 MIS Lecture Notes7 School Bus Garage Case Relational Database Schema