Many-to-Many Relationships

Concept

• Many-to-many relationships occur when records in one table can relate to multiple records in another.
• A join table is used to map these relationships.

Example

• Exercise Table: Has a primary key exerciseID.
• Workout Table: Has a primary key workoutID.
• WorkoutExercise Join Table: Uses both workoutID and exerciseID as foreign keys, allowing exercises to appear in multiple workouts.

Source

• Wikipedia - Database Schema