Hibernate TransientPropertyValueException保存数据时 [英] Hibernate TransientPropertyValueException When saving data

问题描述

我试图使用hibernate将数据插入数据库。以下是我将如何执行该操作

  session.beginTransaction（）; 
 pojo.StuDetails stu = new StuDetails（）; 
 stu.setFName（f_name）; 
 stu.setLName（l_name）; 
 stu.setSex（sex）; 
 stu.setDob（dob）; 
 
 pojo.Subject sub = new Subject（subject，day，time）; 
 pojo.SubjectHasStuDetails shs = new SubjectHasStuDetails（stu，sub）; 
 
 session.save（shs）; 
 session.getTransaction（）。commit（）; 
  

但它给了我一个错误，说：

线程main中的异常
org.hibernate.TransientPropertyValueException：非空属性
引用一个瞬态值 - 瞬态实例必须保存在
之前当前操作

这是我的学生资料实体

  public class StuDetails实现了java.io.Serializable {
 
 
 private Integer id; 
 private String FName; 
 private String LName; 
私人字符串性别; 
 private String dob; 
 private Set subjectHasStuDetailses = new HashSet（）; 
 ... 
 //构造函数和getter，setters 
  

我的StudentDetails hbm .xml

 < hibernate-mapping> 
< class name =pojo.StuDetailstable =stu_detailscatalog =laravel_testoptimistic-lock =version> 
< id name =idtype =java.lang.Integer> 
< column name =id/> 
< generator class =identity/> 
< / id> 
< property name =FNametype =string> 
< column name =f_namelength =45not-null =true/> 
< / property> 
< property name =LNametype =string> 
< column name =l_namelength =45not-null =true/> 
< / property> 
< property name =sextype =string> 
< column name =sexlength =45not-null =true/> 
< / property> 
< property name =dobtype =string> 
< column name =doblength =45not-null =true/> 
< / property> 
< set name =subjectHasStuDetailsestable =subject_has_stu_detailsinverse =truelazy =truefetch =select> 
< key> 
< column name =stu_details_idnot-null =true/> 
< / key> 
<一对多等级=pojo.SubjectHasStuDetails/> 
< / set> 
< / class> 
< / hibernate-mapping> 
  

My Subject Entity看起来像

private Integer id;
private String subName;
私人字符串日;
私人字符串时间;
private Set subjectHasStuDetailses = new HashSet（）;

...
//构造函数和getter，setters

Subject.hbm.xml

 < hibernate-mapping> 
< class name =pojo.Subjecttable =subjectcatalog =laravel_testoptimistic-lock =version> 
< id name =idtype =java.lang.Integer> 
< column name =id/> 
< generator class =identity/> 
< / id> 
< property name =subNametype =string> 
< column name =sub_namelength =45not-null =true/> 
< / property> 
< property name =daytype =string> 
< column name =daylength =45not-null =true/> 
< / property> 
< property name =timetype =string> 
< column name =timelength =45not-null =true/> 
< / property> 
< set name =subjectHasStuDetailsestable =subject_has_stu_detailsinverse =truelazy =truefetch =select> 
< key> 
< column name =subject_idnot-null =true/> 
< / key> 
<一对多等级=pojo.SubjectHasStuDetails/> 
< / set> 
 
< / class> 
< / hibernate-mapping> 
  

以下是SubjetcHasStuDetails实体

private Integer id;
私人StuDetails stuDetails;
私人主题;
...
//构造函数和getter，setters

SubjectHasStuDetials.hbm .xml

 < hibernate-mapping> 
< class name =pojo.SubjectHasStuDetailstable =subject_has_stu_details
 catalog =laravel_testoptimistic-lock =version> 
< id name =idtype =java.lang.Integer> 
< column name =id/> 
< generator class =identity/> 
< / id> 
<多对一名称=stuDetailsclass =pojo.StuDetailsfetch =select> 
< column name =stu_details_idnot-null =true/> 
< /多对一> 
 < column name =subject_idnot-null =true/> 
< /多对一> 
< / class> 
< / hibernate-mapping> 
  

有人可以帮我解决这个错误，谢谢..

$ b $在您的 SubjectHasStuDetials.hbm.xml 中使这些成为可能更改：

 <多对一名称=stuDetailsclass =pojo.StuDetails提取=selectcascade =all> 
< column name =stu_details_idnot-null =true/> 
< /多对一> 
 < column name =subject_idnot-null =true/> 
< /多对一> 
  

添加 cascade =all 属性为 stuDetails 和 subject 多对一标签。

• 级联属性是强制性的，当我们在对象之间应用关系
  时，级联属性传输操作如果我们编写 cascade =all，那么在父类的变化对象也会对子类对象产生影响，如果我们写了cascade =all
  ，那么所有对父对象的插入，删除，更新操作都会影响到子对象。例如：如果我们对父
  类对象应用插入（或更新或删除）操作，那么子类对象也将被存储到
  数据库中。
/ li>

I am trying to insert data to the DB using hibernate . Here is how I going perform that action

    session.beginTransaction();
    pojo.StuDetails stu = new StuDetails();
    stu.setFName(f_name);
    stu.setLName(l_name);
    stu.setSex(sex);
    stu.setDob(dob);

    pojo.Subject sub = new Subject(subject, day, time);
    pojo.SubjectHasStuDetails shs = new SubjectHasStuDetails(stu, sub);

    session.save(shs);
    session.getTransaction().commit();  

But It gives me an error saying

Exception in thread "main" org.hibernate.TransientPropertyValueException: Not-null property references a transient value - transient instance must be saved before current operation

Here is my student details entity

 public class StuDetails  implements java.io.Serializable {


 private Integer id;
 private String FName;
 private String LName;
 private String sex;
 private String dob;
 private Set subjectHasStuDetailses = new HashSet();
 ...
 //constructors and getters, setters

My StudentDetails hbm.xml

<hibernate-mapping>
    <class name="pojo.StuDetails" table="stu_details" catalog="laravel_test" optimistic-lock="version">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="identity" />
        </id>
        <property name="FName" type="string">
            <column name="f_name" length="45" not-null="true" />
        </property>
        <property name="LName" type="string">
            <column name="l_name" length="45" not-null="true" />
        </property>
        <property name="sex" type="string">
            <column name="sex" length="45" not-null="true" />
        </property>
        <property name="dob" type="string">
            <column name="dob" length="45" not-null="true" />
        </property>
        <set name="subjectHasStuDetailses" table="subject_has_stu_details" inverse="true" lazy="true" fetch="select">
            <key>
                <column name="stu_details_id" not-null="true" />
            </key>
            <one-to-many class="pojo.SubjectHasStuDetails" />
        </set>
    </class>
</hibernate-mapping>

My Subject Entity looks like

 public class Subject  implements java.io.Serializable {


 private Integer id;
 private String subName;
 private String day;
 private String time;
 private Set subjectHasStuDetailses = new HashSet();

 ...
 //constructors and getters, setters

Subject.hbm.xml

<hibernate-mapping>
    <class name="pojo.Subject" table="subject" catalog="laravel_test" optimistic-lock="version">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="identity" />
        </id>
        <property name="subName" type="string">
            <column name="sub_name" length="45" not-null="true" />
        </property>
        <property name="day" type="string">
            <column name="day" length="45" not-null="true" />
        </property>
        <property name="time" type="string">
            <column name="time" length="45" not-null="true" />
        </property>
        <set name="subjectHasStuDetailses" table="subject_has_stu_details" inverse="true" lazy="true" fetch="select">
            <key>
                <column name="subject_id" not-null="true" />
            </key>
            <one-to-many class="pojo.SubjectHasStuDetails" />
        </set>

    </class>
</hibernate-mapping>

Here is the SubjetcHasStuDetails Entity

 public class SubjectHasStuDetails  implements java.io.Serializable {


 private Integer id;
 private StuDetails stuDetails;
 private Subject subject;
 ...
 //constructors and getters, setters

SubjectHasStuDetials.hbm.xml

<hibernate-mapping>
    <class name="pojo.SubjectHasStuDetails" table="subject_has_stu_details" 
           catalog="laravel_test" optimistic-lock="version">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="identity" />
        </id>
        <many-to-one name="stuDetails" class="pojo.StuDetails" fetch="select">
            <column name="stu_details_id" not-null="true" />
        </many-to-one>
        <many-to-one name="subject" class="pojo.Subject" fetch="select" >
            <column name="subject_id" not-null="true" />
        </many-to-one>
    </class>
</hibernate-mapping>

Can someone help me on this error please ... Thanks..

解决方案

In your SubjectHasStuDetials.hbm.xml make these changes :

<many-to-one name="stuDetails" class="pojo.StuDetails" fetch="select" cascade="all">
            <column name="stu_details_id" not-null="true" />
        </many-to-one>
<many-to-one name="subject" class="pojo.Subject" fetch="select" cascade="all" >
            <column name="subject_id" not-null="true" />
        </many-to-one>

Add cascade="all" attribute to both stuDetails and subject many-to-one tags.

• Cascade attribute is mandatory, when ever we apply relationship between objects, cascade attribute transfers operations done on one object onto its related child objects
• If we write cascade = "all" then changes at parent class object will be effected to child class object too, if we write cascade = "all" then all operations like insert, delete, update at parent object will be effected to child object also.
• Example: if we apply insert(or update or delete) operation on parent class object, then child class objects will also be stored into the database.

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