Question

我有一个简单的父/子obj双向关系定义。我想执行级联删除，这样当删除父级时，所有子级都将被删除，同时从父级删除一次。这是我的pojo类声明：

@Entity
@Table(name = "Agent_Assignment", schema = "xxx", catalog = "AAA")
public class AgentAssignment {
    private Set<AgentAssignmentAttr> attributes = new HashSet<AgentAssignmentAttr>();

    @OneToMany( fetch=FetchType.EAGER, cascade=CascadeType.ALL, orphanRemoval=true )
    @JoinColumn(name="Agent_Assignment_GUID")
    public Set<AgentAssignmentAttr> getAttributes() {
        return attributes;
    }

    public void setAttributes(Set<AgentAssignmentAttr> attributes) {
        this.attributes = attributes;
    }

}

@Entity
@Table(name = "Agent_Assignment_Attr", schema = "xxx", catalog = "AAA")
public class AgentAssignmentAttr {
    private AgentAssignment asgnmnt = null;

    @ManyToOne( fetch=FetchType.EAGER )
    @JoinColumn(name="Agent_Assignment_GUID", insertable=false, updatable=false)
    public AgentAssignment getAssignment() {
        return asgnmnt;
    }

    public void setAssignment(AgentAssignment assignment) {
        this.asgnmnt = assignment;
    }
}

要删除的代码是：

AgentAssignment assgnmnt = (...some HQL query to returns the AgentAssignment obj)
getSession().delete(assgnmnt);

执行上述删除调用时，会抛出异常：

org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement

基本上，当登录Hibernate日志的SQL执行时，它不会调用＆＃34;更新＆＃34;在Agent_Assignment_Attr表中它应该删除的行，而是调用＆＃34;更新＆＃34;在行上设置外键列＆＃34; Agent_Assignement_GUID＆＃34;为null，如下所示：

/* delete one-to-many com.cs.mytime.acr.model.AgentAssignment.attributes */ update
        MyTime.dbo.Agent_Assignment_Attr 
    set
        Agent_Assignment_GUID=null 
    where
        Agent_Assignment_GUID=?
2014/08/22 16:31:10.430 [TRACE] <http-bio-8080-exec-5> (BasicBinder.bind:81) - binding parameter [1] as [VARCHAR] - [CA91A4F3-6F7E-4188-B299-8E9DF17F0385]

感谢任何人帮助，看看是否有我错过的东西和正确的解决方案。感谢。

Answer 1

您的映射是错误的。双向关联只能定义关联的映射方式一次。您所拥有的是两个不同的，无关的关联碰巧使用同一列。映射应该是

@OneToMany(mappedBy="assignment", fetch=FetchType.EAGER, cascade=CascadeType.ALL, orphanRemoval=true )
public Set<AgentAssignmentAttr> getAttributes() {
    return attributes;
}

其中mappedBy说：“我是在AgentAssignmentAttr.assignment上定义和映射的双向关联的反面，

@ManyToOne( fetch=FetchType.EAGER )
@JoinColumn(name="Agent_Assignment_GUID")
public AgentAssignment getAssignment() {
    return asgnmnt;
}

Answer 2

为了获得删除而不是更新，我不得不使用这种方法：

@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, orphanRemoval = true)
@JoinColumn(name = "PARENT_ID", referencedColumnName = "PARENT_ID", updatable = false)
private List<ChildEntity> children;

Hibernate Cascade删除一对多调用SQL＆＃34;更新＆＃34;而不是＆＃34;删除＆＃34;

2 个答案: