如何在休眠标准上使用连接列？

Question

我有 3 个实体通过一对一关系加入。我的目标是使用 match.status != null 处的休眠条件获取实体。以及如何告诉 hibernate 不要将 algo 实体加入到结果中，应该是 (pick.algo = null)。

@Entity
public class Pick {
  @Id
  @GeneratedValue(strategy=GenerationType.AUTO)
  private int pid;

  @Column(columnDefinition="DATETIME")
  private Date insertTime;

  @Column(columnDefinition="DATETIME")
  private Date setupResTime;

  @OneToOne
  private DbMatch match;

  @OneToOne
  private Algo algo;

  @Transient
  private Integer algoID;
  ....

条件查询：

public List<Pick> getPicksHistory(){
    Criteria criteria = session.createCriteria(Pick.class);  
    criteria.add(Restrictions.isNotNull("match.status"));
    return criteria.list();

}

Answer 1

您可以添加别名并将条件应用于别名

Criteria criteria = session.createCriteria(Pick.class);  
criteria.createAlias("match", "match", JoinType.INNER_JOIN); //<---
criteria.add(Restrictions.isNotNull("match.status"));

要获取空值，您可以使用例如JoinType.LEFT_OUTER_JOIN

Answer 2

来自休眠文档 (http://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html_single/#querycriteria-associations) :

Criteria criteria = session.createCriteria(Pick.class);
criteria.createAlias("match", "m");
criteria.add(Restrictions.isNotNull("m.status"));
criteria.setFetchMode("algo", FetchMode.LAZY);
criteria.list();

如何在休眠标准上使用连接列？

How to use joined columns on hibernate criteria?

java

mysql

hibernate