[FIXED] Join Table to create composite Primary Key

Issue

I have two tables student and categories. Student and category has ManyToMnay relationship.

@Entity
@Getter
@Setter
@Table(name = "student")
 public class Student {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "student_id",nullable = false)
private Integer id;

@Column(name = "student_name")
private String name;


@ManyToMany(cascade = {CascadeType.ALL})
@JoinTable(name = "student_has_subject",

        joinColumns = @JoinColumn(name = "student_student_id"),
        inverseJoinColumns = @JoinColumn(name = "student_subject_id"))
private List<Subject> subjects = new ArrayList<>()

}

Subject.class

@Entity
@Getter
@Setter
@Table(name = "subject")
public class Subject {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "subject_id", nullable = false)
    private Integer id;

    @Column(name = "subject_name",nullable = false)
    private String name;

    @ManyToMany(mappedBy = "subjects")
    private List<Student> students = new ArrayList<>();
}

But when I execute this in IDE. student_has_subject Table created but without creating primary key.

mysql> describe workflow_services;
+-------------+------------+------+-----+---------+-------+
| Field       | Type       | Null | Key | Default | Extra |
+-------------+------------+------+-----+---------+-------+
| student_id  | bigint(20) | NO   | PRI | NULL    |       |
| subject_id  | bigint(20) | NO   | PRI | NULL    |       |
+-------------+------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

How could I make both forieng key as primary.

When I create this no primary key created.

How to create new table name student_has_subject with all column as primary key

Solution

Preferred way to map a ManyToMany is using a Set rather than a List - ManytoMany.

Also using a Set will generate a PK in the join table

Answered By - johnnyutts
Answer Checked By - Mary Flores (JavaFixing Volunteer)