JPA 2.0标准和谓词分组

Question

在复合谓词方面,我遇到了Hibernate EntityManager 3.5.3-Final的问题.

示例(不是实际的代码片段,但想法应该清楚):

CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
Predicate predicate1 = criteriaBuilder.conjunction();
Predicate predicate2 = criteriaBuilder.conjunction();
// These are Boolean expression with common Root
predicate1.getExpressions().add(expression1);
predicate1.getExpressions().add(expression2);
predicate2.getExpressions().add(expression3);
predicate2.getExpressions().add(expression4);
//...
query.where(criteriaBuilder.or(predicate1, predicate2));

现在,我希望有类似的东西:

SELECT ... FROM ... WHERE (expression1 AND expression2) OR (expression3 AND expression4)

但是我最终得到:

SELECT ... FROM ... WHERE expression1 AND expression2 OR expression3 AND expression4

我做了一些非常错误的事情还是Hibernate问题？

Answer 1

根据SQL规范,这两个语句意味着相同的事情.语句是否包含()并不重要,因此Hibernate不使用它们.优先顺序是这样的,类似于1 + 2*3与1+(2*3)相同.