CS377: Database Design - Relational Data Model
Activity Goals
The goals of this activity are:- To express database table relationships through mathematical abstraction
- To describe the advantages and disadvantages of different database engines
Supplemental Reading
Feel free to visit these resources for supplemental background reading material.The Activity
Directions
Consider the activity models and answer the questions provided. First reflect on these questions on your own briefly, before discussing and comparing your thoughts with your group. Appoint one member of your group to discuss your findings with the class, and the rest of the group should help that member prepare their response. Answer each question individually from the activity on the Class Activity Questions discussion board. After class, think about the questions in the reflective prompt and respond to those individually in your notebook. Report out on areas of disagreement or items for which you and your group identified alternative approaches. Write down and report out questions you encountered along the way for group discussion.Model 1: Domains and Relations
\(FirstName \times LastName \times Age = \{(firstname, lastname, age) : firstname \in \{a-zA-Z\}+, lastname \in \{a-zA-Z\}+, age \in \mathbb{Z}^{+}\}\)
Questions
- If the domain of the
Agefield is all positive numbersAge > 0, what is the domain ofFirstName? - Translate the cartesian product formula into your own words describing the nature of the table it defines.
- This table relation has degree 3. What do you think that means?
- Is it ever appropriate to have the same row in a table more than once? What is the alternative if such a situation is needed?
- Suppose you wish to track the history and provenance of a record. For example, if someone changes their name, a record of both names and the dates during which each name was valid would be included. What tables and fields might you add to do this?