有两个类：Survey和Questions，问卷类和题目类，它们是多对多的关系，即：一张试卷可以有多个题目，一个题目可以属于多个试卷，我用两个一对多，数据库用中间表来实现，并有第三个类SurveyQuestions.
surveuy类如下： [code="java"]//问卷实体：包括各种属性
@Entity
@Table(name="_survey")
public class Survey {
private int id;// 问卷ID
private String name;// 问卷标题
private String des;// 问卷描述或者备注
private boolean state;// 状态：是否开放
private SurveyType surveyType;// 问卷类型
private int count;// 问卷数量限制
private Date createTime;// 问卷创建时间
private Date publishTime;// 问卷发布时间
private Date deadline;// 问卷截止提交日期
private String password;// 问卷访问密码
private boolean grade;//是否是打分问卷
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDes() {
return des;
}
public void setDes(String des) {
this.des = des;
}
public boolean isState() {
return state;
}
public void setState(boolean state) {
this.state = state;
}
@ManyToOne
@JoinColumn(name = "type_id")
public SurveyType getSurveyType() {
return surveyType;
}
public void setSurveyType(SurveyType surveyType) {
this.surveyType = surveyType;
}
public int getCount() {
return count;
}
public void setCount(int count) {
this.count = count;
}
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
public Date getPublishTime() {
return publishTime;
}
public void setPublishTime(Date publishTime) {
this.publishTime = publishTime;
}
public Date getDeadline() {
return deadline;
}
public void setDeadline(Date deadline) {
this.deadline = deadline;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public boolean isGrade() {
return grade;
}
public void setGrade(boolean grade) {
this.grade = grade;
}[/code]
questions类 [code="java"] @Entity
@Table(name="_questions")
public class Questions {
private int id;// 问题主键ID
private QuestionType questionType;// 问题类型
private String head;// 问题题目
private String body;// 问题主体
private String answer;// 预留字段，如果是网上答卷，则是答案
private String remarks;// 预留字段，备注
private int number;// 选项个数
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getHead() {
return head;
}
public void setHead(String head) {
this.head = head;
}
public String getBody() {
return body;
}
public void setBody(String body) {
this.body = body;
}
public String getAnswer() {
return answer;
}
public void setAnswer(String answer) {
this.answer = answer;
}
public String getRemarks() {
return remarks;
}
public void setRemarks(String remarks) {
this.remarks = remarks;
}
@ManyToOne(fetch=FetchType.LAZY)
@JoinColumn(name = "type_id")
public QuestionType getQuestionType() {
return questionType;
}
public void setQuestionType(QuestionType questionType) {
this.questionType = questionType;
}
@Column(nullable = true)
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
}[/code]
surveyQuestion类 [code="java"]package com.questionnaire.model;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;
@Entity
@Table(name = "_surveyquestion")
public class SurveyQuestion {
private int id;// 问卷题库关联表ID，主键
private Survey survey;// 对应问卷ID，外键
private Questions questions;// 对应题目ID，外键
private int number;// 题号，即该题目在本问卷的题号
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
this.userIp = userIp;
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "survey_id")
public Survey getSurvey() {
return survey;
}
public void setSurvey(Survey survey) {
this.survey = survey;
}
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "questions_id")
public Questions getQuestions() {
return questions;
}
public void setQuestions(Questions questions) {
this.questions = questions;
}
}[/code]
我想实现删除题目时删除_questions表里的数据，同时删除_surveyQuestion表里的数据。当然survey同样？怎样实现呢？
