CODEWITHSUNDEEP
javahibernateone-to-manymany-to-onedistinct-values
chiperortiz
chiperortiz

Reputation: 4991

Java Hibernate one to many fetch using Criteria

I have a entity like this

public class Student
{
    private School school; //many to one...
    //setter and getters omitted
}

public class School
{
    private Set<Student>students; //Students...
    private Set<Owner>owners; //Owners one to many....
}

I have my code is quite easy..

 final Criteria criteria = session.createCriteria(Student.class)
 .add(filters)
 .setFetchMode("school",FetchMode.JOIN);
 final List<Student>students = criteria.list();

But I would like to retrieve the Owners as well. Later I could do:

for(final Student student:students)student.getSchool().getOwners.size();

But this would generate another distinct SQL query.

But I want to do it in a single Query is this possible?

I have tried:

final Criteria criteria = session.createCriteria(Student.class)
.add(filters);
final Criteria ownerCriteria = criteria
            .createCriteria("school","school")               
            .createAlias("owners","owners");
final List<Student>students = criteria.list();

But this do not works because when I navigate through it:

for(final Student student:students)student.getSchool().getOwners.size();

Exception in thread "main" org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role

Exception is thrown! Even I can see the inner join in Hibernate SQL console.. but seems the Owner collection is not populate.

Is there a workaround for this?

Upvotes: 0

Views: 1028

Answers (1)

nayakam
nayakam

Reputation: 4239

You could use

criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);

Upvotes: 1

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