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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. Relational Database Development So Far. E-R diagrams
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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 90-728 MIS Lecture Notes
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? 90-728 MIS Lecture Notes
1 1 M M INSPECTION_TYPE INSPECTION INSPLINK Health Inspection Problem Extensions -I • Inspection event may be represented two ways: • transaction-in-rows • transaction-in-columns Example: vs: What are the pros and cons of each approach? 90-728 MIS Lecture Notes
Permit ID PERMIT STATUS M 1 has a ESTABLISHMENT (0,M) (1,1) Permit ID 1 1 M M PERMIT STATUS has a has a ESTABLISHMENT PERMIT (0,M) (1,1) (1,1) (0,M) 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? 90-728 MIS Lecture Notes
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? 90-728 MIS Lecture Notes
School Bus Garage E-R Diagram 90-728 MIS Lecture Notes
School Bus Garage Case Relational Database Schema 90-728 MIS Lecture Notes