In this example an InvestigationType has many SampleType’s. If I load an InvestigationType via em (entity manager) find it also loads the samples.
- InvestigationType inv2 = (InvestigationType) em.find(
- InvestigationType.class, inv.getId());
- System.out.println(“Inv2 ID=”+inv2.getId());
- System.out.println(“Inv2 Title=”+inv2.getTitle());
- assertTrue(inv2.getSample().size() == 2);
However, if I load a SampleType the investigation field is null, unless I refresh the object.
- // Get a sample
- SampleType s3 = (SampleType) em.find(
- SampleType.class, inv2.getSample().get(0).getId());
- InvestigationType inv3 = s3.getInvestigation();
From my understanding I should not have to do this as the fetching should be the same in both instances, ie resolving the parent by default. Similarly, if I query for both objects the references are correctly loaded.
List items = em.createQuery(“SELECT i, s FROM au.edu.archer.schemas.datadeposition.SampleType s, IN(s.investigation) i WHERE s.id=2”).getResultList();
If someone could tell me why this is so, please let me know. Else, at least I have a working example now.
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