How to specify foreign key with the join column?

Question

My code is as below. I am using the spring boot with jpa and postgresql database I need user friendly name as foreign key.


    @Entity
    @Table(name="course_table")
    public class Course extends BaseAuditingEntity {

    @ManyToMany(cascade = CascadeType.REMOVE, fetch = FetchType.EAGER)
    @JoinTable(name = "course_program_table", joinColumns = @JoinColumn(name = "course_id", referencedColumnName = "course_id", foreignKey = @ForeignKey(name = "fk_program_id")), inverseJoinColumns = @JoinColumn(name = "program_id", referencedColumnName = "program_id", foreignKey = @ForeignKey(name = "fk_course_id")))
    private List programs;
    }

I have given the name of foreign key using the @ForeignKey annotation but when I see db it is showing the randomly created foreignkey name.

CREATE TABLE course_program_table
(
    course_id integer NOT NULL,
    program_id integer NOT NULL,
    CONSTRAINT fk_28c95hl4nqclyvyxuduei5nbf FOREIGN KEY (program_id)
        REFERENCES public.program_table (program_id) MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE NO ACTION,
    CONSTRAINT fk_5sainywquv8yyu24pjk3jptn7 FOREIGN KEY (course_id)
        REFERENCES public.course_table (course_id) MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE NO ACTION
)

I need foreign key as mentioned in the annotation like fk_program_id and fk_course_id.

Thanks in advance.

Did hibernate generate that table? You don't even need to specify a FK in your code. It is purely optional — XtremeBaumer, Mar 29 '18 at 13:18
Yes, Hibernate is generating the table but I want the name of FK is as mentioned in annotation. — parthivrshah, Mar 29 '18 at 13:23
Check this link. Could be duplicate of https://stackoverflow.com/questions/16564789/changing-the-generated-name-of-a-foreign-key-in-hibernate — Madhusudana Reddy Sunnapu, Mar 29 '18 at 13:27
Have you tried to specify the `@ForeignKey` explicitly instead of have it nested in other annotations? — XtremeBaumer, Mar 29 '18 at 13:34
@parthivrshah what is the error when you try to specify the FK explicitly — Thufir, Mar 29 '18 at 14:37
It is not giving any error but in the db it creates randomly. — parthivrshah, Mar 30 '18 at 03:45

score 4 · Answer 1 · 2018-03-30T07:30:44.267

4

With a join table this is how you should specify it

@ManyToMany
@JoinTable(name = "course_program_table", 
    joinColumns = @JoinColumn(name = "course_id", ...)
    foreignKey = @ForeignKey(name = "fk_program_id"), 
    inverseJoinColumns = @JoinColumn(name = "program_id", ...)
    inverseForeignKey = @ForeignKey(name = "fk_course_id"))
private List programs;

This is how I do it with the JPA provider I use (not Hibernate), and that is why the @JoinTable has the "foreignKey"/"inverseForeignKey" attributes (the FKs are on/owned by the join table).

If that doesn't work then you need to be looking at raising a bug on your chosen JPA provider.

edited Mar 30 '18 at 07:30

answered Mar 29 '18 at 14:48

I have tried this ...It is not giving any error but in the database it creates randomly generated foreign key. – parthivrshah Mar 30 '18 at 03:52
So you need to raise a bug on the jpa provider you are using – Mar 30 '18 at 05:00
Works correctly with Quarkus Hibernate 1.13.7. The accepted answer didn't work for me, beacause there is no `inverseName` in `@javax.persistence.ForeignKey` – TomasZ. Jun 18 '21 at 11:05

score 3 · Accepted Answer · answered Apr 25 '18 at 09:38

@ManyToMany(cascade = CascadeType.REMOVE, fetch = FetchType.EAGER)
@JoinTable(name = "tten_courseservice_course_program_table", joinColumns = @JoinColumn(name = "course_id", referencedColumnName = "course_id"), inverseJoinColumns = @JoinColumn(name = "program_id", referencedColumnName = "program_id"))
@ForeignKey(name="fk_tten_courseservice_course_table_course_id",inverseName="fk_tten_courseservice_program_table_program_id")
private List<ProgramEntity> programs;``

I have tried this and now I am able to generate foreign key name properly.

Hope it will help other.

How to specify foreign key with the join column?

2 Answers2