[FIXED] How can I do LEFT_JOIN in ComponentType with CriteriaQuery API

Issue

I have the following mappings:

ProductProviderDetail.class

@Entity
@Table
public class ProductProviderDetail {
    // other fields
    @Embedded
    private AuditInformation auditInformation;
    // getters and setters
}

AuditInformation.class

@Embeddable
public class AuditInformation  {
    // other fields
    @ManyToOne(fetch = FetchType.LAZY, optional = true) // default is true but I want to make a point here
    @JoinColumn(name = "head", referencedColumnName = "id")
    private Head head;
    // getters and setters
}

As you can see there's an association inside of a ComponentType such that it's optional. Querying this property would look like

CriteriaBuilder builder = session.getCriteriaBuilder();
CriteriaQuery<Tuple> query = builder.createTupleQuery();
Root<ProductProviderDetail > root = query.from(ProductProviderDetail .class);
    
query.multiselect(root.get("auditInformation").get("head"));

Since the association is optional, I'd like to make a LEFT_JOIN which, in this case, would be something like

root.get("auditInformation").join("head", JoinType.LEFT);

The thing is root.get("auditInformation") would return an instance of SingularAttributePath which is not capable of doing a .join() operation. Is there any other ways that I can achieve this type of query with CriteriaQuery API? Thank you for any help.

Solution

I found a solution after browsing the site. Apparently, we're supposed to do .join() on both the component and attribute level. Like so.

root.join("auditInformation").join("head", JoinType.LEFT);

Answered By - Ngọc Hy