Is it possible to convert a 'many-to-many' relationship into a 'one-to-many' association?

Yes, a "many-to-many" relationship can be transformed into a "one-to-many" relationship using an intermediate entity (table).

Instead of a direct connection between two entities, a third table (for example, "Link") is created, which contains foreign keys to both related tables. Thus, each of the original tables will have a "one-to-many" relationship with this intermediate table.

Example:

• Table Students
• Table Courses
• Table Enrollments with fields student_id and course_id

In Java with JPA, it looks like this:

@Entity
public class Student {
    @Id
    private Long id;

    @OneToMany(mappedBy = "student")
    private List<Enrollment> enrollments;
}

@Entity
public class Course {
    @Id
    private Long id;

    @OneToMany(mappedBy = "course")
    private List<Enrollment> enrollments;
}

@Entity
public class Enrollment {
    @Id
    private Long id;

    @ManyToOne
    private Student student;

    @ManyToOne
    private Course course;
}

Thus, the "many-to-many" relationship is implemented through two "one-to-many" relationships with an intermediate entity.