Week 5: Relational Mapping and Normalization

Due: Wednesday, Sep 23rd

Thursday's class maps EER diagrams to tables. This reading also covers normalization, which we do not spend class time on but which explains why the mapping rules produce the tables they do.

Prompt

Paste the standard prompt, then paste this block.

Topic: Turning a data model into tables, and why designs get
split into multiple tables.

My learning objectives:
- Map entities and relationships to tables with primary and
  foreign keys.
- Explain what a foreign key constraint enforces, and what
  happens when a statement violates one.
- Recognize redundancy and update anomalies in a table design,
  and explain how splitting one table into related tables
  resolves them.

Teach me these concepts. Give me an analogy or a comparison
before you give me the definition, and don't move on until I
have restated the idea in my own words.

Sources

• 2.3 Converting ERD to a relational model
• 1.7 Keys and constraints
• 3.3 Normalization

How far to go on normalization

Section 3.3 goes further into normal forms than this course needs. Read for the problem, not the algorithm: what goes wrong when the same fact is stored in two places, and how splitting tables fixes it. You should come away knowing that third normal form is the usual target and roughly what it asks for. You will not be asked to decompose a relation on an exam.