Java 如何在实体关系不直接的情况下使用休眠条件连接多个表？
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How to join Multiple tables using hibernate criteria where entity relationship is not direct?
提问by seal
I have three entities. those are:
我有三个实体。那些是：
@Entity
public class Organization {
@Id
private long id;
@Column
private String name;
}
@Entity
public class Book {
@Id
private Long id;
@Column
private String name;
@ManyToOne
private Organization organization;
}
@Entity
public class Account {
@Id
private Long id;
@Column
private String name;
@ManyToOne
private Book book;
}
In these three entities I would like to perform following sql:
在这三个实体中，我想执行以下 sql：
SELECT acc.name, acc.id
FROM account acc
JOIN book b on acc.book_id = b.id
JOIN organization org on b.organization_id = org.id
WHERE org.name = 'XYZ'
In this case Accountentity has no relation with the Organizationentity directly. Accountentity has the relation via Book. How can I achieve this using hibernate criteria dynamic query?
在这种情况下，Account实体与Organization实体没有直接关系。Account实体通过 有关系Book。如何使用休眠条件动态查询来实现这一点？
采纳答案by jpprade
you can do like this :
你可以这样做：
Criteria accountCriteria = getCurrentSession().createCriteria(Account.class,"acc");
Criteria bookCriteria = accountCriteria .createCriteria("book","b");
Criteria orgCriteria = bookCriteria.createCriteria("organization","org");
orgCriteria.add(Restrictions.eq("name", "XYZ"));
ProjectionList properties = Projections.projectionList();
properties.add(Projections.property("name"));
properties.add(Projections.property("id"));
accountCriteria.setProjection(properties);
accountCriteria.list();
回答by LynAs
Another way
其它的办法
public List<Account> getAccountListByOrgName(String name){
return sessionFactory.getCurrentSession().createCriteria(Account.class)
.createAlias("book", "book")
.createAlias("book.organization", "organization")
.add(Restrictions.eq("organization.name", name))
.list();
}
