删除一对多关系中的儿童 [英] Delete children in one to many relationship

问题描述

有一个相当基本的Hibernate 3.6.10实现的问题。

我有两个类，时间表和事件。要完成一个事件的唯一途径是按计划进行，所以我已经建立了一个与有许多事件的时间表的一对多关系。

这里是时间表：

  / ** 
 * 
 * / 
 package com.heavyweightsoftware.leal.model。时间表; 
 
 import java.util.Collection; 
 
 import javax.persistence.CascadeType; 
 import javax.persistence.Column; 
 import javax.persistence.Entity; 
 import javax.persistence.FetchType; 
 import javax.persistence.GeneratedValue; 
 import javax.persistence.GenerationType; 
 import javax.persistence.Id; 
 import javax.persistence.NamedQueries; 
 import javax.persistence.NamedQuery; 
 import javax.persistence.OneToMany; 
 import javax.persistence.Table; 
 
 import com.heavyweightsoftware.leal.helper.DateHelper; 
 import com.heavyweightsoftware.leal.model.Pojo; 
 
 / ** 
 *可以共享的特定事件集合
 * @author Thom 
 * / 
 @Entity 
 @ Table（name =SCHEDULE）
 @NamedQueries（{
 @NamedQuery（name = Schedule.COUNT_SCHED_ID，query =SELECT COUNT（*）+ 
FROM Schedule s+ 
WHERE s.scheduleId =：scheduleId），
 @NamedQuery（name = Schedule.COUNT_SCHED_NAME，query =SELECT COUNT（*）+ 
FROM ScheduleRole r，Schedule s，SystemUser u+ 
WHERE u.email =：email+ 
AND u.id = r.systemUserId+ 
AND r.scheduleId = s.id+ 
 AND s.name =：scheduleName），
 @NamedQuery（name = Schedule.QUERY_EVENTS_BY_USER，query =SELECT r.roleType，s+ 
FROM Schedule s，ScheduleRole r，SystemUser u + 
WHERE u.email =：email+ 
AND u.id = r.systemUserId+ 
AND r.scheduleId = s.id+ 
 ）
} 
）
 public class Schedule扩展Pojo {
 
 public static final int LENGTH_SCHEDULE_ID = 32; 
 public static final String COUNT_SCHED_ID =countScheduleId; 
 public static final String COUNT_SCHED_NAME =countScheduleName; 
 public static final String QUERY_EVENTS_BY_USER =findEventsByUser; 
 
 @Column（name =ID，nullable = false）
 @Id @GeneratedValue（strategy = GenerationType.AUTO）
 private Integer id; 
 
 @Column（name =NAME，nullable = false）
私有字符串名称; 
 
 @Column（name =SCHEDULE_ID，nullable = false，unique = true，length = LENGTH_SCHEDULE_ID）
 private String scheduleId; 
 
 @OneToMany（cascade = CascadeType.ALL，fetch = FetchType.EAGER）
 private Collection< Event>事件; 
 $ b $ *（非Javadoc）
 * @see com.heavyweightsoftware.leal.model.Pojo＃toString（）
 * / 
 @Override 
 public String toString（）{
 StringBuilder sb = new StringBuilder（super.toString（））; 
 sb.append（'|'）; 
 sb.append（getName（））; 
 sb.append（'|'）; 
 sb.append（getScheduleId（））; 
 return sb.toString（）; 
 
 $ b $ *（非Javadoc）
 * @see java.lang.Object＃hashCode（）
 * / 
 @Override 
 public int hashCode（）{
 final int prime = 31; 
 int result = super.hashCode（）; 
 result = prime * result +（（id == null）？0：id.hashCode（））; 
 result = prime * result +（（name == null）？0：name.hashCode（））; 
 result = prime * result 
 +（（scheduleId == null）？0：scheduleId.hashCode（））; 
返回结果; 
 
 $ b / *（非Javadoc）
 * @see java.lang.Object＃equals（java.lang.Object）
 * / 
 @Override 
 public boolean equals（Object obj）{
 if（this == obj）
 return true; 
 if（！super.equals（obj））
 return false; 
 if（getClass（）！= obj.getClass（））
 return false; 
 Schedule other =（Schedule）obj; 
 if（id == null）{
 if（other.id！= null）
 return false; 
} else if（！id.equals（other.id））
 return false; 
 if（name == null）{
 if（other.name！= null）
 return false; 
} else if（！name.equals（other.name））
 return false; 
 if（scheduleId == null）{
 if（other.scheduleId！= null）
 return false; 
} else if（！scheduleId.equals（other.scheduleId））
 return false; 
返回true; 
 
 $ b $ ** 
 * @return the id 
 * / 
 public final Integer getId（）{
 return id; 
 
 $ b $ ** 
 * @param id id设置
 * / 
 public final void setId（Integer id）{
 this.id = id; 
 
 $ b / ** 
 * @返回名称
 * / 
 public final String getName（）{
 return name; 
} 
 
 / ** 
 * @param将名称设置为
 * / 
 public final void setName（String name）{
 this.name = name; 
 
 $ b / ** 
 * @return 
 * / 
 public String getScheduleId（）{
 return scheduleId == null？scheduleId = DateHelper.getUniqueID（）：scheduleId; 
 
 $ b / ** 
 * @param scheduleId 
 * / 
 public void setScheduleId（String scheduleId）{
 this.scheduleId = scheduleId; 
} 
 
 / ** 
 * @返回事件
 * / 
 public Collection< Event> getEvents（）{
返回事件; 
 
 $ b $ ** 
 * @param events设置事件
 * / 
 public void setEvents（Collection< Event> events）{
 this.events = events; 
 
 
 $ / code> 

这里是事件：

  / ** 
 * 
 * / 
 package com.heavyweightsoftware.leal.model.schedule; 
 
 import java.util.Calendar; 
 
 import javax.persistence.Column; 
 import javax.persistence.Entity; 
 import javax.persistence.FetchType; 
 import javax.persistence.GeneratedValue; 
 import javax.persistence.GenerationType; 
 import javax.persistence.Id; 
 import javax.persistence.ManyToOne; 
 import javax.persistence.NamedQueries; 
 import javax.persistence.Table; 
 import javax.persistence.Temporal; 
 import javax.persistence.TemporalType; 
 
 import com.heavyweightsoftware.leal.model.Pojo; 
 $ b $ / ** 
 *日历中的特定事件条目
 * @author Thom 
 * / 
 @Entity 
 @Table （b 
 
 
 
 $ public class Event {随机生成的事件ID的长度
 * / 
 private static final int LENGTH_EVENT_ID = 32; 
 
 @Column（name =ID，nullable = false）
 @Id @GeneratedValue（strategy = GenerationType.AUTO）
 private Integer id; 
 
 @Column（name =START_TIME）
 @Temporal（TemporalType.TIMESTAMP）
私人日历开始; 
 
 @Column（name =END_TIME）
 @Temporal（TemporalType.TIMESTAMP）
私人日历结束; 
 
 @Column（name =EVENT_NAME，nullable = false）
 private String eventName; 
 
 @Column（name =EVENT_ID，nullable = false，unique = true，length = LENGTH_EVENT_ID）
 private String eventId; 
 
 @ManyToOne（fetch = FetchType.EAGER）
 private调度时间表; 
 
 @Column（name =LOCATION）
私人字符串位置; 
 $ b $ *（非Javadoc）
 * @see java.lang.Object＃hashCode（）
 * / 
 @Override 
 public int hashCode （）{
 final int prime = 31; 
 int result = super.hashCode（）; 
 result = prime * result +（（end == null）？0：end.hashCode（））; 
 result = prime * result 
 +（（eventName == null）？0：eventName.hashCode（））; 
 result = prime * result +（（id == null）？0：id.hashCode（））; 
 result = prime * result 
 +（（location == null）？0：location.hashCode（））; 
 result = prime * result 
 +（（schedule == null）？0：schedule.hashCode（））; 
 result = prime * result +（（start == null）？0：start.hashCode（））; 
返回结果; 
 
 $ b / *（非Javadoc）
 * @see java.lang.Object＃equals（java.lang.Object）
 * / 
 @Override 
 public boolean equals（Object obj）{
 if（this == obj）
 return true; 
 if（！super.equals（obj））
 return false; 
 if（getClass（）！= obj.getClass（））
 return false; 
其他事件=（Event）obj; 
 if（end == null）{
 if（other.end！= null）
 return false; 
} else if（！end.equals（other.end））
 return false; 
 if（eventName == null）{
 if（other.eventName！= null）
 return false; 
} else if（！eventName.equals（other.eventName））
 return false; 
 if（id == null）{
 if（other.id！= null）
 return false; 
} else if（！id.equals（other.id））
 return false; 
 if（location == null）{
 if（other.location！= null）
 return false; 
} else if（！location.equals（other.location））
 return false; 
 if（schedule == null）{
 if（other.schedule！= null）
 return false; 
} else if（！schedule.equals（other.schedule））
 return false; 
 if（start == null）{
 if（other.start！= null）
 return false; 
} else if（！start.equals（other.start））
 return false; 
返回true; 
 
 $ b $ *（非Javadoc）
 * @see com.heavyweightsoftware.leal.model.Pojo＃toString（）
 * / 
 @Override 
 public String toString（）{
 StringBuilder sb = new StringBuilder（super.toString（））; 
 sb.append（'|'）; 
 sb.append（getEventName（））; 
 sb.append（'|'）; 
 sb.append（getTimestamp（getStart（）））; 
 sb.append（' - '）; 
 sb.append（getTimestamp（getEnd（）））; 
 sb.append（| scheduleId =）; 
 sb.append（getSchedule（）。toString（））; 
 sb.append（'|'）; 
 sb.append（getLocation（））; 
 return sb.toString（）; 
 
 $ b $ ** 
 * @return the id 
 * / 
 public final Integer getId（）{
 return id; 
 
 $ b $ ** 
 * @param id id设置
 * / 
 public final void setId（Integer id）{
 this.id = id; 
} 
 
 / ** 
 *事件的开始日期以UTC 
 * @返回起点
 * / 
 public final日历getStart（）{
 return start; 
} 
 
 / ** 
 *事件的开始日期以UTC 
 * @param开始，开始设置
 * / 
 public final void setStart（Calendar start）{
 this.start = start; 
} 
 
 / ** 
 *事件的结束日期以UTC表示b $ b * @结束
 * / 
 public final日历getEnd（）{
 return end; 
} 
 
 / ** 
 *事件的结束日期以UTC 
 * @param结尾，以设置
 * / 
 public final void setEnd（Calendar end）{
 this.end = end; 
 
 $ b $ ** 
 * @return eventId 
 * / 
 public String getEventId（）{
 return eventId; 
 
 $ b $ ** 
 * @param eventId eventId设置
 * / 
 public void setEventId（String eventId）{
 this.eventId = eventId; 
 
 $ b $ ** b $ b * @return the eventName 
 * / 
 public final String getEventName（）{
 return eventName; 
 
 $ b / ** 
 * @param eventName要设置的事件名称
 * / 
 public final void setEventName（String eventName）{
 this.eventName = eventName; 
 
 $ b $ ** 
 * @返回位置
 * / 
 public final String getLocation（）{
 return location; 
 
 $ b $ ** 
 * @param location要设置的位置
 * / 
 public final void setLocation（String location）{
 this.location = location; 
 
 $ b $ ** 
 * @返回计划
 * / 
 public Sc​​hedule getSchedule（）{
 return schedule; 
} 
 
 / ** 
 * @param安排时间表设定
 * / 
 public void setSchedule（Schedule schedule）{
 this.schedule = schedule; 
 
 
  

除了删除以外，一切正常。当我在春季实施我的DAO并尝试删除我的日程安排时，它会在事件中引发完整性约束。如果我先尝试删除事件，它也不起作用。

  getHibernateTemplate.delete（schedule）; 
  

我该怎么做？



我查阅了休眠删除级联，但我不明白这是如何适用于我的情况。

下面是我写的delete方法：

  public void delete Schedule sched）{
 //获取事件
 Collection< Event> events = sched.getEvents（）; 
 //删除所有的孩子
 getHibernateTemplate（）。deleteAll（events）; 
 //清空缓冲区
 getHibernateTemplate（）。flush（）; 
 //清除集合
 sched.getEvents（）。clear（）; 
 //删除时间表
 super.delete（sched）; 
} 
  

谢谢。 b $ b

  @OneToMany 
 
 （cascade = CascadeType.ALL，fetch = FetchType.EAGER，orphanRemoval = true）
 private Collection< Event>事件; 
  

然后事件：

  @ManyToOne（fetch = FetchType.EAGER）
 private schedule schedule; 
  

然后删除方法。

<$ p $ b $ public void delete（Schedule sched）
抛出DataAccessException {
//获取事件
Collection< Event> events = sched.getEvents（）;
//清除集合
events.clear（）;
//清空缓冲区
getHibernateTemplate（）。flush（）;
//重新加载$ ​​b $ b sched = retrieve（sched）;
//删除时间表
super.delete（sched）;
}


感谢您的帮助！

Having an issue with a pretty basic Hibernate 3.6.10 implementation.

I have two classes, schedule and event. The only way to get to an event is through schedule, so I've modeled as a one to many relationship with a schedule having many events.

Here is schedule:

/**
 * 
 */
package com.heavyweightsoftware.leal.model.schedule;

import java.util.Collection;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.OneToMany;
import javax.persistence.Table;

import com.heavyweightsoftware.leal.helper.DateHelper;
import com.heavyweightsoftware.leal.model.Pojo;

/**
 * A particular collection of events that can be shared
 * @author Thom
 */
@Entity
@Table(name = "SCHEDULE")
@NamedQueries( {
    @NamedQuery(name = Schedule.COUNT_SCHED_ID,      query =  "SELECT COUNT(*) " +
                                                              "FROM Schedule s " +
                                                              "WHERE s.scheduleId = :scheduleId"),
    @NamedQuery(name = Schedule.COUNT_SCHED_NAME,    query =  "SELECT COUNT(*) " +
                                                              "FROM   ScheduleRole r, Schedule s, SystemUser u " +
                                                              "WHERE  u.email = :email " +
                                                               " AND u.id = r.systemUserId " +
                                                               " AND r.scheduleId = s.id " +
                                                               " AND s.name = :scheduleName "),
    @NamedQuery(name = Schedule.QUERY_EVENTS_BY_USER, query =  "SELECT  r.roleType, s " +
                                                               "FROM    Schedule s, ScheduleRole r, SystemUser u " +
                                                               "WHERE   u.email = :email " +
                                                               "  AND   u.id = r.systemUserId " +
                                                               "  AND   r.scheduleId = s.id " +
                                                               " ")
    }
)
public class Schedule extends Pojo {

    public static final int        LENGTH_SCHEDULE_ID        = 32;
    public static final String     COUNT_SCHED_ID            = "countScheduleId";
    public static final String     COUNT_SCHED_NAME          = "countScheduleName";
    public static final String     QUERY_EVENTS_BY_USER      = "findEventsByUser";

    @Column(name = "ID", nullable=false)
    @Id @GeneratedValue(strategy=GenerationType.AUTO)
    private Integer     id;

    @Column(name = "NAME", nullable=false)
    private String      name;

    @Column(name = "SCHEDULE_ID", nullable=false, unique=true, length=LENGTH_SCHEDULE_ID)
    private String      scheduleId;

    @OneToMany(cascade = CascadeType.ALL, fetch=FetchType.EAGER)
    private Collection<Event>   events;

    /* (non-Javadoc)
     * @see com.heavyweightsoftware.leal.model.Pojo#toString()
     */
    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder(super.toString());
        sb.append('|');
        sb.append(getName());
        sb.append('|');
        sb.append(getScheduleId());
        return sb.toString();
    }

    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = super.hashCode();
        result = prime * result + ((id == null) ? 0 : id.hashCode());
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        result = prime * result
                + ((scheduleId == null) ? 0 : scheduleId.hashCode());
        return result;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (!super.equals(obj))
            return false;
        if (getClass() != obj.getClass())
            return false;
        Schedule other = (Schedule) obj;
        if (id == null) {
            if (other.id != null)
                return false;
        } else if (!id.equals(other.id))
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        if (scheduleId == null) {
            if (other.scheduleId != null)
                return false;
        } else if (!scheduleId.equals(other.scheduleId))
            return false;
        return true;
    }

    /**
     * @return the id
     */
    public final Integer getId() {
        return id;
    }

    /**
     * @param id the id to set
     */
    public final void setId(Integer id) {
        this.id = id;
    }

    /**
     * @return the name
     */
    public final String getName() {
        return name;
    }

    /**
     * @param name the name to set
     */
    public final void setName(String name) {
        this.name = name;
    }

    /**
     * @return
     */
    public String getScheduleId() {
        return scheduleId == null?scheduleId = DateHelper.getUniqueID():scheduleId;
    }

    /**
     * @param scheduleId
     */
    public void setScheduleId(String scheduleId) {
        this.scheduleId = scheduleId;
    }

    /**
     * @return the events
     */
    public Collection<Event> getEvents() {
        return events;
    }

    /**
     * @param events the events to set
     */
    public void setEvents(Collection<Event> events) {
        this.events = events;
    }
}

And here is Event:

/**
 * 
 */
package com.heavyweightsoftware.leal.model.schedule;

import java.util.Calendar;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
import javax.persistence.NamedQueries;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

import com.heavyweightsoftware.leal.model.Pojo;

/**
 * A particular event entry in a calendar
 * @author Thom
 */
@Entity
@Table(name = "EVENT")
@NamedQueries( {
    }
)
public class Event extends Pojo {

    /**
     * Length of the randomly generated event ID
     */
    private static final int            LENGTH_EVENT_ID             = 32;

    @Column(name = "ID", nullable=false)
    @Id @GeneratedValue(strategy=GenerationType.AUTO)
    private Integer     id;

    @Column(name = "START_TIME")
    @Temporal(TemporalType.TIMESTAMP)
    private Calendar    start;

    @Column(name = "END_TIME")
    @Temporal(TemporalType.TIMESTAMP)
    private Calendar    end;

    @Column(name = "EVENT_NAME", nullable=false)
    private String      eventName;

    @Column(name = "EVENT_ID", nullable=false, unique=true, length=LENGTH_EVENT_ID)
    private String      eventId;

    @ManyToOne(fetch=FetchType.EAGER)
    private Schedule    schedule;

    @Column(name = "LOCATION")
    private String      location;

    /* (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = super.hashCode();
        result = prime * result + ((end == null) ? 0 : end.hashCode());
        result = prime * result
                + ((eventName == null) ? 0 : eventName.hashCode());
        result = prime * result + ((id == null) ? 0 : id.hashCode());
        result = prime * result
                + ((location == null) ? 0 : location.hashCode());
        result = prime * result
                + ((schedule == null) ? 0 : schedule.hashCode());
        result = prime * result + ((start == null) ? 0 : start.hashCode());
        return result;
    }

    /* (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (!super.equals(obj))
            return false;
        if (getClass() != obj.getClass())
            return false;
        Event other = (Event) obj;
        if (end == null) {
            if (other.end != null)
                return false;
        } else if (!end.equals(other.end))
            return false;
        if (eventName == null) {
            if (other.eventName != null)
                return false;
        } else if (!eventName.equals(other.eventName))
            return false;
        if (id == null) {
            if (other.id != null)
                return false;
        } else if (!id.equals(other.id))
            return false;
        if (location == null) {
            if (other.location != null)
                return false;
        } else if (!location.equals(other.location))
            return false;
        if (schedule == null) {
            if (other.schedule != null)
                return false;
        } else if (!schedule.equals(other.schedule))
            return false;
        if (start == null) {
            if (other.start != null)
                return false;
        } else if (!start.equals(other.start))
            return false;
        return true;
    }

    /* (non-Javadoc)
     * @see com.heavyweightsoftware.leal.model.Pojo#toString()
     */
    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder(super.toString());
        sb.append('|');
        sb.append(getEventName());
        sb.append('|');
        sb.append(getTimestamp(getStart()));
        sb.append('-');
        sb.append(getTimestamp(getEnd()));
        sb.append("|scheduleId=");
        sb.append(getSchedule().toString());
        sb.append('|');
        sb.append(getLocation());
        return sb.toString();
    }

    /**
     * @return the id
     */
    public final Integer getId() {
        return id;
    }

    /**
     * @param id the id to set
     */
    public final void setId(Integer id) {
        this.id = id;
    }

    /**
     * The start date of the event in UTC
     * @return the start
     */
    public final Calendar getStart() {
        return start;
    }

    /**
     * The start date of the event in UTC
     * @param start the start to set
     */
    public final void setStart(Calendar start) {
        this.start = start;
    }

    /**
     * The end date of the event in UTC
     * @return the end
     */
    public final Calendar getEnd() {
        return end;
    }

    /**
     * The end date of the event in UTC
     * @param end the end to set
     */
    public final void setEnd(Calendar end) {
        this.end = end;
    }

    /**
     * @return the eventId
     */
    public String getEventId() {
        return eventId;
    }

    /**
     * @param eventId the eventId to set
     */
    public void setEventId(String eventId) {
        this.eventId = eventId;
    }

    /**
     * @return the eventName
     */
    public final String getEventName() {
        return eventName;
    }

    /**
     * @param eventName the eventName to set
     */
    public final void setEventName(String eventName) {
        this.eventName = eventName;
    }

    /**
     * @return the location
     */
    public final String getLocation() {
        return location;
    }

    /**
     * @param location the location to set
     */
    public final void setLocation(String location) {
        this.location = location;
    }

    /**
     * @return the schedule
     */
    public Schedule getSchedule() {
        return schedule;
    }

    /**
     * @param schedule the schedule to set
     */
    public void setSchedule(Schedule schedule) {
        this.schedule = schedule;
    }
}

Everything is working fine except delete. When I implement my DAO through spring and try to delete my schedule, it throws an Integrity Constraint on the Event. It doesn't work if I try to delete the events first either.

getHibernateTemplate.delete(schedule);

How do I do this?

I have reviewed Hibernate Delete Cascade but I do not see how this applies in my situation.

Here is the delete method that I've written:

public void delete(Schedule sched) {
    //grab the events
    Collection<Event> events = sched.getEvents();
    //delete all children
getHibernateTemplate().deleteAll(events);
//flush the buffers
    getHibernateTemplate().flush();
    //clear the collection
    sched.getEvents().clear();
    //delete the schedule
    super.delete(sched);
}

Thanks.

解决方案

After trial and error and research, here's where I ended up.

@OneToMany(cascade = CascadeType.ALL, fetch=FetchType.EAGER, orphanRemoval=true)
private Collection<Event>   events;

And then Event:

@ManyToOne(fetch=FetchType.EAGER)
private Schedule    schedule;

And then the delete method.

public void delete(Schedule sched) 
        throws DataAccessException{
    //grab the events
    Collection<Event> events = sched.getEvents();
    //clear the collection
    events.clear();
    //flush the buffers
    getHibernateTemplate().flush();
    //reload
    sched = retrieve(sched);
    //delete the schedule
    super.delete(sched);
}

Thanks for all the help!

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