如何使用休眠CRITERIA編寫此聯接查詢

Question

select ptm.* from ProofTestMaster ptm LEFT JOIN 
ProofTestApplicationMap ptam on ptm.proofTestID = ptam.proofTestID 
LEFT JOIN ProofTestComapartmentMap ptcm on ptm.proofTestID = ptcm.proofTestID 
where (ptam.applicationID = 3 and ptm.isDeleted = 0) or 
(ptcm.compartmentID = 4 and ptm.isDeleted = 0)

其中ProofTestApplicationMap和ProofTestComapartmentMap是映射表，並且它們在Java結尾沒有實體。

Answer 1

最好為查詢添加適當的縮進。 優點是：

• 您將了解easilly查詢
• 其他人也會很快理解。

所以我為你做了。 現在查詢看起來像：

select 
    ptm.* 
from ProofTestMaster ptm 
    LEFT JOIN ProofTestApplicationMap ptam on ptm.proofTestID = ptam.proofTestID 
    LEFT JOIN ProofTestComapartmentMap ptcm on ptm.proofTestID = ptcm.proofTestID 
where 
    (ptam.applicationID = 3 and ptm.isDeleted = 0) or 
    (ptcm.compartmentID = 4 and ptm.isDeleted = 0);

現在，下面是帶有靜態元模型的CriteriaBuilder的實現：

CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<Long> criteriaQuery = criteriaBuilder.createQuery(Long.class);

Root<ProofTestMaster> mainRoot = criteriaQuery.from(ProofTestMaster.class);

Join<ProofTestMaster, ProofTestApplicationMap> firstJoin = mainRoot.join(ProofTestMaster_.proofTestID, JoinType.LEFT);
Join<ProofTestMaster, ProofTestComapartmentMap> secondJoin = mainRoot.join(ProofTestMaster_.proofTestID, JoinType.LEFT);

Predicate p1 = criteriaBuilder.equal(firstJoin.get(ProofTestApplicationMap_.applicationID),3);
Predicate p2 = criteriaBuilder.equal(mainRoot.get(ProofTestMaster_.isDeleted),0);
Predicate p3 = criteriaBuilder.equal(secondJoin.get(ProofTestComapartmentMap_.compartmentID), 4);
Predicate p4 = criteriaBuilder.and(p1,p2);
Predicate p5 = criteriaBuilder.and(p3,p2);
Predicate p6 = criteriaBuilder.or(p4,p5);

criteriaQuery.where(p6);

criteriaQuery.select(criteriaBuilder.count(mainRoot));

Long count = entityManager.createQuery(criteriaQuery).getSingleResult();

如果您看到上面的代碼，則總共有6個謂詞，可以將它們放入List中。 但是為了您的理解，我一直這樣保存。

讓我知道是否有幫助。 謝謝，祝您編程愉快。