Day 5/100: Many-to-Many Relationships - Tags, Associations, and Bulk Operations

Part of my 100 Days of Code journey. Today we tackle one of the most important database patterns. The Challenge Implement a tagging system with many-to-many relationships and add bulk operations for efficiency. The Problem: Tasks need flexible organization. Fixed categories don't work because: One task can belong to multiple categories (urgent AND work AND client-facing) Categories can have multiple tasks Users want custom labels, not predefined options The Solution: Many-to-many relationships via junction tables, plus bulk operations for power users. Why Many-to-Many Matters One-to-Many relationships (what we've used so far): User ──┬─→ Task 1 ├─→ Task 2 └─→ Task 3 Each task has ONE user. Simple! Many-to-Many relationships (what we need): Task 1 ──┬─→ Tag: urgent └─→ Tag: work Task 2 ──┬─→ Tag: urgent ├─→ Tag: personal └─→ Tag: home Tag: urgent ──┬─→ Task 1 └─→ Task 2 Problem: Can't use a simple foreign key! If we add tag_id to tasks table: ❌ Task can only have ONE tag ❌ Need multiple