将标准转换为自我加入的分离标准 [英] convert criteria to detached criteria for self join

问题描述

我想知道我是否可以将此标准转换为分离标准。我不正确理解分离标准。可以有人帮助。

  Criteria crit = sessionC.createCriteria（OP_DOCTOR_VISIT.class，OPDV1）; 
 crit.createAlias（OPDV1.OP_VISIT，OPDV2，JoinType.LEFT_OUTER_JOIN，Restrictions.and（Restrictions.eq（OPDV2.FORM，NEW），Restrictions.ge（OPDV2.USER_DATETIME ，fromdate），Restrictions.le（OPDV2.USER_DATETIME，todate）））; 
 crit.add（Restrictions.ge（OPDV1.USER_DATETIME，fromdate））; 
 crit.add（Restrictions.le（OPDV1.USER_DATETIME，todate））; 
 ProjectionList p1 = Projections.projectionList（）; 
 p1.add（Projections.alias（Projections.count（OPDV1.OP_VISIT_ID），TOTAL））; 
 p1.add（Projections.count（OPDV2.FORM））; 
 p1.add（Projections.alias（Projections.sqlGroupProjection（date（this_.USER_DATETIME）as createdDate，createdDate，new String [] {createdDate}，new Type [] {StandardBasicTypes.DATE} ），DAT））; 
 crit.setProjection（p1）; 
  

是否可以重写上面的内容，以便我可以避免在给定的POJO中使用@OneToMany

POJO

  @Entity 
 @Table （name =OP_DOCTOR_VISIT）
 @SQLDelete（sql =UPDATE OP_DOCTOR_VISIT SET DELETED ='DELETED'WHERE OP_VISIT_ID =？and VERSION_UPDATES =？）
 @Where（clause =DELETED< 'DELETED'）
 public class OP_DOCTOR_VISIT实现Serializable {
 
 @Id 
 @GeneratedValue（strategy = GenerationType.IDENTITY）
 @Column（name =OP_VISIT_ID ）
私人长OP_VISIT_ID; 
 
 @OneToMany（mappedBy =OP_VISIT_ID，cascade = CascadeType.ALL，fetch = FetchType.LAZY）
 @LazyCollection（LazyCollectionOption.EXTRA）
 @Fetch（FetchMode.SELECT ）
私人列表< OP_DOCTOR_VISIT> OP_VISIT; 
 
 public Long getOP_VISIT_ID（）{
 return OP_VISIT_ID; 
} 
 
 public void setOP_VISIT_ID（Long OP_VISIT_ID）{
 this.OP_VISIT_ID = OP_VISIT_ID; 
} 
 
公开列表< OP_DOCTOR_VISIT> getOP_VISIT（）{
返回OP_VISIT; 
} 
 
 public void setOP_VISIT（List< OP_DOCTOR_VISIT> OP_VISIT）{
 this.OP_VISIT = OP_VISIT; 
} 
 
} 
  

解决方案

DetachedCriteria crit = DetachedCriteria.forClass（OP_DOCTOR_VISIT.class，OPDV1）;

条件允许您在不使用会话的情况下创建查询。然后，您可以在任意会话中执行搜索。

实际上，当使用另一个会话或新会话使用分离标准时，您应该仔细考虑 ，并创建会话）。

它们对于创建一些连接条件，子查询以及在当前会话之外进行查询非常有用。
另一个常见用途是用于代码重用。

如果您使用Spring并选择使用HibernateTemplate，则它不会提供createCriteria（）方法。
您只能找到** DetachedCriteria。

I would like to know if i can convert this criteria into a detached criteria. I am not understanding detached criteria correctly. can some one help.

Criteria crit = sessionC.createCriteria(OP_DOCTOR_VISIT.class, "OPDV1");
crit.createAlias("OPDV1.OP_VISIT", "OPDV2", JoinType.LEFT_OUTER_JOIN, Restrictions.and(Restrictions.eq("OPDV2.FORM", "NEW"), Restrictions.ge("OPDV2.USER_DATETIME", fromdate), Restrictions.le("OPDV2.USER_DATETIME", todate)));
    crit.add(Restrictions.ge("OPDV1.USER_DATETIME", fromdate));
    crit.add(Restrictions.le("OPDV1.USER_DATETIME", todate));
    ProjectionList p1 = Projections.projectionList();
    p1.add(Projections.alias(Projections.count("OPDV1.OP_VISIT_ID"), "TOTAL"));
    p1.add(Projections.count("OPDV2.FORM"));
    p1.add(Projections.alias(Projections.sqlGroupProjection("date(this_.USER_DATETIME) as createdDate", "createdDate", new String[]{"createdDate"}, new Type[]{StandardBasicTypes.DATE}), "DAT"));
    crit.setProjection(p1);

Is it possible to rewrite the above so that I could avoid using "@OneToMany" in my POJO given below.

POJO

@Entity
@Table(name = "OP_DOCTOR_VISIT")
@SQLDelete(sql = "UPDATE OP_DOCTOR_VISIT SET DELETED = 'DELETED' WHERE OP_VISIT_ID = ? and VERSION_UPDATES = ?")
@Where(clause = "DELETED <> 'DELETED'")
public class OP_DOCTOR_VISIT implements Serializable {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "OP_VISIT_ID")
private Long OP_VISIT_ID;

@OneToMany(mappedBy = "OP_VISIT_ID", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
@LazyCollection(LazyCollectionOption.EXTRA)
@Fetch(FetchMode.SELECT)
private List<OP_DOCTOR_VISIT> OP_VISIT;

    public Long getOP_VISIT_ID() {
        return OP_VISIT_ID;
    }

    public void setOP_VISIT_ID(Long OP_VISIT_ID) {
        this.OP_VISIT_ID = OP_VISIT_ID;
    }

    public List<OP_DOCTOR_VISIT> getOP_VISIT() {
        return OP_VISIT;
    }

    public void setOP_VISIT(List<OP_DOCTOR_VISIT> OP_VISIT) {
        this.OP_VISIT = OP_VISIT;
    }

}

解决方案

DetachedCriteria crit = DetachedCriteria.forClass(OP_DOCTOR_VISIT.class, "OPDV1");

The detached criteria allows you to create the query without Session. Then you can execute the search in an arbitrary session.

In fact you should think carefully when use detached criterias using another, or a new, session (no cache, and creation of the session).

They are most useful for make some join conditions, subselects, and to query outside the current session. Another common use is for code reuse.

If you are using Spring and choose to use HibernateTemplate, it doesn't provide createCriteria() method. You will find only **DetachedCriteria.

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