Topic 9b
Writing Database Queries
Prior to Class
By the end of this topic students should be able to:
- Identify potential redundancy in a dataset and suggest how different relation tables can reduce/eliminate that redundancy.
- Define the concept of a/an [ attribute | relation | tuple ]
- Identify and/or explain the purpose of the [JOIN | PROJECT | SELECT ] operation in database queries.
- Given a description of a database and one or more relational operations, explain the results of the operation(s).
In class
Discussion
Let's walk through this idea for a bit.
Checking for Understanding
Answer the following questions from your textbook. The answers to all Q&E questions are in the back of your book in Appendix F.
- p 489, #1
- p 489, #2
- p 489, #3
Extra Help
The answers to the CFU questions above are provided in the back of the book. The following videos explain how we would arrive at some of those answers.