CODEWITHSUNDEEP
springspring-data-jpaspring-data
Andrey Yaskulsky
Andrey Yaskulsky

Reputation: 2526

Spring Data many-to-many, fetching all entities whose relationship does not contain items

I have the following relation:

    @Entity
    @Table(name = "User")
    public class User {
    
        @JsonIgnore
        @ManyToMany
        @JoinTable(
                name = "user_group",
                joinColumns = {@JoinColumn(name = "user_id", referencedColumnName = "id")},
                inverseJoinColumns = {@JoinColumn(name = "group_id", referencedColumnName = "id")}
        )
    private List<Group> groups = new ArrayList<>();
     .......
}

So I have User <--> Group many-to-many relation.

I need to fetch all users that do not have associations with groups at all - get all users whose groups list is empty.

Is there a way to fetch users like that with a usage of spring data?

Any help is appreciated,

Thanks

Upvotes: 1

Views: 645

Answers (1)

Gundamaiah
Gundamaiah

Reputation: 786

If you want to fetch the users who don't have groups, then try the below method in UserRepository.

public interface UserRepository  extends JpaRepository<User,Long> {

    Optional<List<User>> findAllByGroupsEmpty();
}

By above method, spring data jpa will fetch the users who groups are empty.

Upvotes: 1

Related Questions