Module 3: Multi-Table Queries

Module Overview

Explore relationships between tables and learn advanced querying techniques.

Learning Objectives

  • Understand and implement table relationships
  • Master SQL JOIN operations
  • Write complex multi-table queries
  • Implement these concepts using Knex.js

Module Content

1. Understanding Table Relationships

Learn about different types of database relationships:

  • One-to-one relationships
  • One-to-many relationships
  • Many-to-many relationships
  • Designing proper relationships

2. SQL JOIN Operations

Master the different types of SQL JOINs:

  • INNER JOIN
  • LEFT JOIN
  • RIGHT JOIN
  • FULL OUTER JOIN
  • CROSS JOIN

3. Complex Queries with Knex.js

Learn how to write multi-table queries using Knex.js:

  • Joins with Knex.js
  • Subqueries and derived tables
  • Combining WHERE, GROUP BY, and HAVING
  • Ordering and limiting results

4. Query Optimization

Techniques for improving query performance:

  • Using indexes effectively
  • Writing efficient JOIN statements
  • Avoiding N+1 query problems
  • Analyzing query performance

Additional Resources

SQLite JOIN Tutorial Knex.js JOIN Documentation W3Schools SQL JOIN Tutorial Guided Project Repository

Reminder

JOIN operations are fundamental to working with relational databases. Practice different JOINs to understand how they affect result sets.