休眠問題未保存到數據庫

Question

我遇到了休眠問題。 我嘗試沒有成功。 我有一個架構，其中有Category，Attribute，AttributeOption。 例如，類別可以是“計算機”，並且其各自的屬性可以是“ RAM”，“硬盤”，例如，“ RAM”可以具有屬性選項“ 512MB”，“ 1024MB”。好。

現在我有另一個要求。 “類別”可以有許多子類別。 例如，“計算機”可以將“筆記本電腦”或“筆記本”作為子類別。 現在這些子類別本身就是類別類別

then I get this scheme:

        1. Category  ------>Category
           A category can contain many sub categories
           e.g. A computer can be a notebook or laptop

        2. Category ------>Attribure
           A category can have many attribute
           A  notebook can have RAM , Hard Disk, Screen Size

        3. Attribute  ------>AttributeOption
           An Attribute can have many attribute options
           e.g. RAM can be 512 MB, 1024 MB

這些是我的課程，沒有他們的getter和setter

Class Category:
public class Category implements IsSerializable 
{
    private long CategoryId;
    private String CategoryName;
    private Set <Category> SubCategory=new HashSet <Category> ();
    private Set <Attribute> AllAttributes= new HashSet  <Attribute>();

}
Category Mapping File:


 <?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Dec 16, 2010 8:07:32 AM by Hibernate Tools 3.4.0.Beta1 -->
<hibernate-mapping>
    <class name="com.BiddingSystem.Models.Category" table="CATEGORY">
        <id name="CategoryId" type="long">
            <column name="CATEGORYID" />
            <generator class="native" />
        </id>
        <property name="CategoryName" type="java.lang.String">
            <column name="CATEGORYNAME" />
        </property>
        <many-to-one name="ParentCategory" class="com.BiddingSystem.Models.Category">
            <column name="PARENTCATEGORYID" />
        </many-to-one>
        <set name="SubCategory" inverse="true" lazy="true" cascade="all" fetch="join">
            <key>
                <column name="PARENTCATEGORYID" />
            </key>
            <one-to-many class="com.BiddingSystem.Models.Category" />
        </set>
        <set name="AllAttributes" table="ATTRIBUTE" inverse="false" lazy="true">
            <key>
                <column name="CATEGORYID" />
            </key>
            <one-to-many class="com.BiddingSystem.Models.Attribute" />
        </set>
    </class>
</hibernate-mapping>


Class Attribute:
public class Attribute 
{
    private long AttributeId;
    private String AttributeName;
    private Set <AttributeOption> Options= new HashSet <AttributeOption>();
}

Attribute Mapping File:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Dec 16, 2010 5:25:09 AM by Hibernate Tools 3.4.0.Beta1 -->
<hibernate-mapping>
    <class name="com.BiddingSystem.Models.Attribute" table="ATTRIBUTE">
        <id name="AttributeId" type="long">
            <column name="ATTRIBUTEID" />
            <generator class="native" />
        </id>
        <property name="AttributeName" type="java.lang.String">
            <column name="ATTRIBUTENAME" />
        </property>
        <set name="Options" table="ATTRIBUTEOPTION" inverse="false"  cascade="all">
            <key>
                <column name="ATTRIBUTEID" />
            </key>
            <one-to-many class="com.BiddingSystem.Models.AttributeOption" />
        </set>
    </class>
</hibernate-mapping>


Class AttributeOption:
public class AttributeOption 
{
    private long AttributeOptionId;
    private String Option;
    private String SQLValue;
}
Attribute Mapping File:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Dec 16, 2010 5:25:09 AM by Hibernate Tools 3.4.0.Beta1 -->
<hibernate-mapping>
    <class name="com.BiddingSystem.Models.AttributeOption" table="ATTRIBUTEOPTION">
        <id name="AttributeOptionId" type="long">
            <column name="ATTRIBUTEOPTIONID" />
            <generator class="native" />
        </id>
        <property name="Option" type="java.lang.String">
            <column name="OPTION" />
        </property>
        <property name="SQLValue" type="java.lang.String">
            <column name="SQLVALUE" />
        </property>
    </class>
</hibernate-mapping>

我正在嘗試以下。 我沒有收到任何錯誤，但是它沒有保存“筆記本電腦”，它是“計算機”的類別，否則所有內容都已保存。 所以我認為問題出在類別映射文件的這一部分：

<set name="SubCategory" table="CATEGORY" cascade="all">
            <key>
                <column name="CATEGORYID" />
            </key>
            <one-to-many class="com.BiddingSystem.Models.Category" />
        </set>



This is part of my program  


    Category C=new Category();
    C.setCategoryName("Computer");
    AttributeOption R512= new AttributeOption();R512.setOption("512");R512.setSQLValue("512");
    AttributeOption R1024= new AttributeOption();R1024.setOption("1024");R1024.setSQLValue("1024");


        Category C0= new Category();
    C0.setCategoryName("Laptop");

    C.getSubCategory().add(C0);

    Attribute RAM= new Attribute();
    RAM.setAttributeName("RAM");

    RAM.getOptions().add(R512);RAM.getOptions().add(R1024);

    C.getAllAttributes().add(RAM);



    Transaction tx = null;
    try
    {
        tx=session.beginTransaction();
        tx.begin();
        session.saveOrUpdate(C);
        tx.commit();
        return true;
    }
    catch (Exception e)
    {
        tx.rollback();
        e.printStackTrace();
        return false;
    }

Answer 1

這似乎有問題：

C0.getSubCategory().add(C0);

不應該是：

C.getSubCategory().add(C0);

Answer 2

Hummm，我在這段代碼中看到了一些需要改進的地方：首先，您應該使用persist（）方法來持久化您的實體。 其次，要持久保存整個對象圖，您必須：a）手動持久保存子對象，然后持久保存“主”對象； 或b）在您的關系上使用Cascade參數，以便持久保留“主要”對象也將觸發相關子對象的持久性。

您可以在此處找到有關級聯的更多信息： http : //docs.jboss.org/hibernate/stable/core/reference/en/html/example-parentchild.html#example-parentchild-cascades

Answer 3

好，我成功了

關鍵是類別映射文件：

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated Dec 16, 2010 8:37:02 AM by Hibernate Tools 3.4.0.Beta1 -->
<hibernate-mapping>
    <class name="com.BiddingSystem.Models.Category" table="CATEGORY">
        <id name="CategoryId" type="long">
            <column name="CATEGORYID" />
            <generator class="native" />
        </id>
        <property name="CategoryName" type="java.lang.String">
            <column name="CATEGORYNAME" />
        </property>

        <many-to-one name="ParentCategory" class="com.BiddingSystem.Models.Category">
            <column name="PARENT_CATEGORY_ID" />
        </many-to-one>

        <set name="SubCategory" lazy="false" cascade="all-delete-orphan" inverse="true">
            <key>
                <column name="PARENT_CATEGORY_ID" />
            </key>
            <one-to-many class="com.BiddingSystem.Models.Category" />
        </set>

        <set name="AllAttributes" table="ATTRIBUTE" inverse="false" lazy="true">
            <key>
                <column name="CATEGORYID" />
            </key>
            <one-to-many class="com.BiddingSystem.Models.Attribute" />
        </set>
    </class>
</hibernate-mapping>