Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Computer Science
Lesson Topic: Understand and identify suitable primary keys
Learning Objective/s:
  • Describe the purpose and characteristics of primary keys in a relational database.
  • Differentiate between natural, surrogate, and composite primary keys.
  • Evaluate criteria (uniqueness, non‑null, stability, simplicity) to select an appropriate primary key.
  • Apply the selection process to design primary keys for given table scenarios.
Materials Needed:
  • Projector or interactive whiteboard
  • Slides on primary key concepts
  • Sample database schema handouts
  • Laptop computers with a DBMS (e.g., MySQL) installed
  • Worksheets with practice questions
  • Sticky notes for quick brainstorming
 Introduction:
Begin with a quick poll: “What unique identifier could you use to distinguish each student in a class?” Connect this to prior learning on tables and records, reminding students that every table needs a single, reliable identifier. Explain that today they will learn how to choose a primary key that meets key criteria and will practice applying it to real‑world examples. Success will be demonstrated by correctly justifying primary key choices in the exit ticket.
Lesson Structure:
  1. Do‑Now (5') – Students list possible identifiers for a given dataset on sticky notes; share quick examples.
  2. Mini‑lecture (10') – Define primary key, review characteristics, and compare natural, surrogate, composite keys using slides.
  3. Guided analysis (12') – Examine the provided Students table; pairs evaluate each field against the criteria, then discuss as a class.
  4. Hands‑on activity (15') – In the computer lab, learners create a simple MySQL table and declare a primary key, experimenting with auto‑increment and composite keys.
  5. Practice questions (10') – Individually answer three scenario questions; teacher circulates to check reasoning.
  6. Check for understanding (5') – Whole‑class review of answers, highlighting common pitfalls and reinforcing the selection checklist.
Conclusion:
Summarise the four key criteria that make a field suitable as a primary key and revisit the checklist created earlier. For the exit ticket, students write one primary key choice for a new scenario and justify it in one sentence. Assign homework to read the textbook section on indexing and prepare a short paragraph on how primary keys affect query performance.