Week 4: Relational Tables — keys, joining and tidying

Learning Objectives

By the end of this week, students will be able to:

• Explain the concept of a primary key and a foreign key
• Perform inner, left, right, and outer joins with pd.merge
• Identify and apply tidy data principles (one observation per row, one variable per column)
• Reshape data between wide and long formats using melt and pivot

Perspectival Reading

Reading: TBD

Reflection Questions

1. The relational model assumes data can be cleanly separated into tables with keys. What kinds of knowledge resist this structure?
2. When tables from different sources are joined, whose data definitions take precedence?
3. Tidy data is a design choice — what does it mean to say data is “messy”?

Slides

View slides

Notebook Demo

Open in Google Colab (link TBD)

Lab Assignment

Week 4 Lab — GitHub Classroom (link TBD)