Courses/Computer Science/CPSC 203/CPSC 203 Template/Lecture Template/Lecture 14

Recap of Key Ideas from Lectures 8 -13

1. We can view the world as sets, and operations on sets. A group of sets and their relationships can be considered a system. (Lecture 8)
2. In particular, if we focus on data in systems, we arrive at the Relational Database meta Model. This provides a consistent way of modelling the data aspects of a system. E-RD diagrams give us a shorthand to sketching the major aspects of such a model, ignoring the details. (Lecture 9).
3. When the world is modelled this way -- we investigate patterns in the data by defining queries. We can build a model of how queries are accomplished via the Query Trace Mechanism. (Lecture 10)
4. For a wide range of systems we could model, there are often a small set of query patterns that allow us to extract useful information. (Lecture 11)
5. Using these query patterns sequentially, we can move up the hierarchy from data to information (and perhaps to knowledge). This requires us to work backwards from our questions, and define a path from raw data to solution (Lecture 12)
6. Finally, we arrive at a "Relational Thinking" style that allows us to look at the world in terms of base sets, and relationships between base sets. (Lecture 13).
7. Some aspects of our relational world view are very algorithmic: e.g. Query Trace Mechanism, Relational Operations, Basic Query Patterns.
8. Other aspects of our relational world view are more heuristic: E-RD drawing, database design.

Concepts

Today we will look at three pairs of concepts that are important to problem solving.

• Deduction and Induction
• Generalization and Specification
• Discovery and Confirmation.

With each pair there is a polar tension between the concepts.

Summary

Often there is a contrast between approaches to Problem Solving, for example:

• Between Induction and Deduction
• Between Generalization and Specification
• Between Discovery (creative) and Confirmation (methodological).

Resources

Renyi, A. 1984. A Diary on Information Theory.

• Source of the "Bar-Kochba" guessing game example.

Polya, G. 1945. A New Aspect of Mathematical Method.

• Source of "Generalization" and "Specification"

Hempel, G. 1966. Philosophy of Natural Science.

• Source of Induction, Deduction Definitions.
• Source of example on Ignaz Semmelweis' investigation of Childbed fever.

Homework

• A Practice Quiz is on BlackBoard (BB) under "Course Documents". Answer sheet will be put on BB for Tuesday's class.

Two additional Database Design practice questions are below.

DB Design Question 1

In the airline industry, a "Ticket" is made up of one-or-more "Coupons" that detail the specifics of the flights you take. The business view of a coupon has the following sets of information.

• Coupon (class, status, confirmed indicator, comment)
• Flight (date of departure, time of departure)
• Airline Route (flight number, scheduled departure date)
• Airline (code, name)
• Airport (code, name)
• Ticket (date of issue, fare, currency)
• Person (name, title, initial)

Create an E-RD based on this information and your general knowledge of air travel.

DB Design Question 2

An organization has the following structure:(represented as nested lists)

• Headquarters (Support Division, Business Systems Division, Sales Division)
• Business Systems Division (Training Department, Development Department, Consultancy Department)
• Consultancy Department (Team A, Team B, Team C)

Create an E-RD based on this organization structure.

Questions

• /Lecture 14 Questions