关于映射对象到数据库中使用Hibernate [英] About Mapping Object To Database Using Hibernate

问题描述

您好，大家好我是新来的冬眠。而我是冲浪的堆栈溢出的休眠相关的主题，我发现这个

Hello guys i am new to hibernate. while i was surfing stack overflow for hibernate related topics i found this

<一个href=\"http://stackoverflow.com/questions/8347350/need-clarification-about-mapping-objects-to-database-annotations-and-one-to-ma\">Need澄清对象映射到数据库，注释和一对多的关系

阅读解决方案，我是一个有点困惑，并开始建立确切的情况，了解背后许多实际的机制之一，这里我使用了Oracle 11g数据库之后。当我运行我的项目Hibernate是自动生成的表和FK关系，而且在插入数据的时候就面临这样的问题（这是显而易见的）

after reading the solution i was a bit confused and started building the exact scenario to understand the actual mechanism behind many to one, where i used oracle 11g database. When i am running my project hibernate is generating the tables and FK relations automatically but in the time of inserting data it facing this problem (which is obvious)

WARN: HHH000437: Attempting to save one or more entities that have a non-nullable association with an unsaved transient entity. The unsaved transient entity must be saved in an operation prior to saving these dependent entities.
Unsaved transient entity: ([com.entity.Authorization#0])
Dependent entities: ([[com.entity.Job#1]])

WARN: HHH000437: Attempting to save one or more entities that have a non-nullable association with an unsaved transient entity. The unsaved transient entity must be saved in an operation prior to saving these dependent entities.
    Unsaved transient entity: ([com.entity.JobFilteration#0])
    Dependent entities: ([[com.entity.Job#1]])
    Non-nullable association(s): ([com.entity.Job.jobfilteration])

我做什么是我所提到的上述议题的解决，我张贴我的实体类（S）请帮我解决这个问题。

i did exactly what was the solution of the above topic I have mentioned, I am posting my entity class(s) Please help me to solve this

类作业

@Entity
@Table(name="JOB")
public class Job implements Serializable {
    @Id 
    @SequenceGenerator(name="person_seq", sequenceName="SEQ_PERSON",initialValue=1,allocationSize=1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE ,generator="person_seq")
    @Column(name="JOB_SERIAL")
    private int id;

    @Column(name="JOB_CATAGORY",nullable=false,length=200,unique=true)
    private String catagory;


    @ManyToOne(fetch=FetchType.LAZY)
    @JoinColumn (name="JOB_AUTHID", nullable = false, updatable = false, insertable = false)
    private Authorization authorization;

    @ManyToOne(fetch=FetchType.LAZY)
    @JoinColumn (name="JOB_JOBFILTERID", nullable = false, updatable = false, insertable = false)
    private JobFilteration jobfilteration;

类JobFilteration

@Entity
@Table(name="JOB_FILTERATION")
public class JobFilteration implements Serializable {
    @Id 
    @SequenceGenerator(name="person_seq", sequenceName="SEQ_PERSON",initialValue=1,allocationSize=1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE ,generator="person_seq")
    @Column(name="FILTER_SERIAL")
    private int id;

    @Column(name="FILTERNAME",nullable=false,length=200)
    private String filtername;

类授权

@Entity
@Table(name="AUTHORIZATION")
public class Authorization implements Serializable {
    @Id 
    @SequenceGenerator(name="person_seq", sequenceName="SEQ_PERSON",initialValue=1,allocationSize=1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE ,generator="person_seq")
    @Column(name="AUTH_ID")
    private int id;

    @Column(name="AUTHORISEDBY",nullable=false,length=200)
    private String authorisedby;

和插入数据我写了一个方法公共无效insertToDB（工作职位）（我用同一顺序的三个类，以节省时间），然后

and for inserting the data i wrote a method public void insertToDB(Job job)(I used same sequence for three classes to save time) and then

JoBDao jobdao= new JoBDao();
Job job= null;
Authorization auth = null;
JobFilteration jfilter = null;

try{
job= new Job();

auth = new Authorization();
    auth.setAuthorisedby("SOMEPERSON");

jfilter = new JobFilteration();
    jfilter.setFiltername("JEE");

job.setCatagory("PERMANENT");
job.setAuthorization(auth);
job.setJobfilteration(jfilter);


jobdao.addPersonandCard(job);

我觉得发生了异常，因为数据被插入在工作表中的其他表（S）将之前。请帮我找出我缺少的是什么？

I think the exception occurred because the data was inserted in the job table before inserting in the other table(s). Please help me to find out what am I missing?

推荐答案

最后我想通了与作业类相关的code的其余部分（类）都OK的问题。在这里，我粘贴正确和修改工作实体

Finally i have figured out the problems associated with the job class the rest of the code(classes) are OK. here i am pasting the correct and modified Job entity

@Entity
@Table(name="JOB")
public class Job implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id 
    @SequenceGenerator(name="person_seq", sequenceName="SEQ_PERSON",initialValue=1,allocationSize=1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE ,generator="person_seq")
    @Column(name="JOB_SERIAL")
    private int id;

    @Column(name="JOB_CATAGORY",nullable=false,length=200,unique=true)
    private String catagory;


    /*   The problem was inside this block */


    @ManyToOne(fetch=FetchType.LAZY,cascade = CascadeType.ALL)
    @JoinColumn (name="JOB_AUTHID", nullable = false)
    private Authorization authorization;                                 

    @ManyToOne(fetch=FetchType.LAZY,cascade = CascadeType.ALL)
    @JoinColumn (name="JOB_JOBFILTERID", nullable = false)
    private JobFilteration jobfilteration;

这篇关于关于映射对象到数据库中使用Hibernate的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！