【发布时间】：2012-02-23 09:31:10
【问题描述】：
论坛成员
我需要你们所有人的帮助。我有两个具有一对多关系的 POJO 模型。 我的项目 pojo 在下面
@Entity
@Table(name = "project")
public class Project implements java.io.Serializable {
private Integer projectid;
private Date enddate;
private String projectdesc;
private String projectname;
private String projecttitle;
private Date startdate;
private Set<Task> tasks = new HashSet<Task>(0);
public Project() {
}
public Project (Integer id,String projectname, String projecttitle, String projectdesc, Date startdate, Date enddate) {
this.projectid = id;
this.enddate = enddate;
this.projectdesc = projectdesc;
this.projectname = projectname;
this.projecttitle = projecttitle;
this.startdate = startdate;
}
public Project(Date enddate, String projectdesc, String projectname,
String projecttitle, Date startdate, Set<Task> tasks) {
this.enddate = enddate;
this.projectdesc = projectdesc;
this.projectname = projectname;
this.projecttitle = projecttitle;
this.startdate = startdate;
this.tasks = tasks;
}
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@Column(name = "projectid", unique = true, nullable = false)
public Integer getProjectid() {
return projectid;
}
public void setProjectid(Integer projectid) {
this.projectid = projectid;
}
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "enddate", length = 19)
public Date getEnddate() {
return enddate;
}
public void setEnddate(Date enddate) {
this.enddate = enddate;
}
@Column(name = "projectdesc")
public String getProjectdesc() {
return projectdesc;
}
public void setProjectdesc(String projectdesc) {
this.projectdesc = projectdesc;
}
@Column(name = "projectname")
public String getProjectname() {
return projectname;
}
public void setProjectname(String projectname) {
this.projectname = projectname;
}
@Column(name = "projecttitle")
public String getProjecttitle() {
return projecttitle;
}
public void setProjecttitle(String projecttitle) {
this.projecttitle = projecttitle;
}
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "startdate", length = 19)
public Date getStartdate() {
return startdate;
}
public void setStartdate(Date startdate) {
this.startdate = startdate;
}
@OneToMany(cascade = CascadeType.ALL, fetch =FetchType.EAGER)
@JoinTable(name = "project_task", joinColumns = { @JoinColumn(name = "projectid") }, inverseJoinColumns = { @JoinColumn(name = "taskid") })
public Set<Task> getTasks() {
return tasks;
}
public void setTasks(Set<Task> tasks) {
this.tasks = tasks;
}
}
我的任务 pojo 是
@Entity
@Table(name = "task")
public class Task implements java.io.Serializable {
private Integer taskid;
private Integer depth;
private Double duration;
private String durationunit;
private Date enddate;
private Integer parentid;
private Integer percentdone;
private Integer priority;
private Date startdate;
private Integer taskindex;
private String taskname;
public Task() {
}
public Task(Integer depth, Double duration, String durationunit,
Date enddate, Integer parentid, Integer percentdone,
Integer priority, Date startdate, Integer taskindex,
String taskname) {
this.depth = depth;
this.duration = duration;
this.durationunit = durationunit;
this.enddate = enddate;
this.parentid = parentid;
this.percentdone = percentdone;
this.priority = priority;
this.startdate = startdate;
this.taskindex = taskindex;
this.taskname = taskname;
}
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@Column(name = "taskid", unique = true, nullable = false)
public Integer getTaskid() {
return taskid;
}
public void setTaskid(Integer taskid) {
this.taskid = taskid;
}
@Column(name = "depth")
public Integer getDepth() {
return depth;
}
public void setDepth(Integer depth) {
this.depth = depth;
}
@Column(name = "duration", precision = 22, scale = 0)
public Double getDuration() {
return duration;
}
public void setDuration(Double duration) {
this.duration = duration;
}
@Column(name = "durationunit")
public String getDurationunit() {
return durationunit;
}
public void setDurationunit(String durationunit) {
this.durationunit = durationunit;
}
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "enddate", length = 19)
public Date getEnddate() {
return enddate;
}
public void setEnddate(Date enddate) {
this.enddate = enddate;
}
@Column(name = "parentid")
public Integer getParentid() {
return parentid;
}
public void setParentid(Integer parentid) {
this.parentid = parentid;
}
@Column(name = "percentdone")
public Integer getPercentdone() {
return percentdone;
}
public void setPercentdone(Integer percentdone) {
this.percentdone = percentdone;
}
@Column(name = "priority")
public Integer getPriority() {
return priority;
}
public void setPriority(Integer priority) {
this.priority = priority;
}
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "startdate", length = 19)
public Date getStartdate() {
return startdate;
}
public void setStartdate(Date startdate) {
this.startdate = startdate;
}
@Column(name = "taskindex")
public Integer getTaskindex() {
return taskindex;
}
public void setTaskindex(Integer taskindex) {
this.taskindex = taskindex;
}
@Column(name = "taskname")
public String getTaskname() {
return taskname;
}
public void setTaskname(String taskname) {
this.taskname = taskname;
}
}
项目 pojo 以一对多的关系与任务相关联。现在我想根据我传递的 id 删除一项任务， 但问题是我无法删除连接表project_task的外键。
我试过下面的代码先删除project_task
Session session = this.hibernateTemplate.getSessionFactory().getCurrentSession();
Query query = session.createQuery("delete from project_task where taskid="+id);
query.executeUpdate();
然后尝试使用以下代码删除任务
Object record = hibernateTemplate.load(Task.class, id);
hibernateTemplate.delete(record);
但不知道为什么这里没有发生删除。任何人都知道我在代码中做错了什么不允许删除发生
【问题讨论】：
-
在任务端使用连接表而不是外键来处理一对多关系是否有特殊原因？
-
我只希望我的数据库是干净的。我的 project_task 表将管理项目和任务之间的所有关系。一个项目 ID 与 project_task 表中的许多任务 ID 相关联。现在一切正常，当我想删除任务时我只是卡住了。你有什么解决方案？