如何使用JPA 2.1 CriteriaDelete从联接表中删除实体 [英] How to delete entities from a joined table with JPA 2.1 CriteriaDelete

问题描述

我想从一名医院删除（ JPA 2.1 ）所有位患者，但遇到问题：
更新/删除条件查询无法定义联接

I want to delete (JPA 2.1) all patients from one Hospital, but run into a problem: UPDATE/DELETE criteria queries cannot define joins

CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaDelete<PatientEntity> delete = cb.createCriteriaDelete(PatientEntity.class);
Root<PatientEntity> root = delete.from(PatientEntity.class);
Join<PatientEntity, HospitalEntity> join = root.join(PatientEntity_.Hospital);
delete.where(cb.equal(join.get(HospitalEntity_.id), id));
Query query = entityManager.createQuery(delete);
query.executeUpdate();

错误：

UPDATE/DELETE criteria queries cannot define joins

我应如何删除所有患者，而无法执行联接？

How should I delete all Patients, while the Join cannot be performed?

推荐答案

您可以使用子查询来为其选择合适的实体和'in'子句。

You can use a subquery that selects proper entities and 'in' clause for that.

CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaDelete<PatientEntity> delete = cb.createCriteriaDelete(PatientEntity.class);
Root<PatientEntity> root = delete.from(PatientEntity.class);


                Subquery<PatientEntity> subquery = delete.subquery(PatientEntity.class);
                Root<PatientEntity> root2 = subquery.from(PatientEntity.class);
                subquery.select(root2);
                /* below are narrowing criteria, based on root2*/   
                Join<PatientEntity, HospitalEntity> join = root2.join(PatientEntity_.Hospital);
                subquery.where(cb.equal(join.get(HospitalEntity_.id), id));


delete.where(root.in(subquery));
Query query = entityManager.createQuery(delete);
query.executeUpdate();

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