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社区首页 >问答首页 >Hibernate多对一延迟加载不起作用

Hibernate多对一延迟加载不起作用
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Stack Overflow用户
提问于 2012-04-06 00:56:10
回答 1查看 13.7K关注 0票数 3

我有一个类和两个多对一映射,我如何延迟加载它们?

我的属性

代码语言:javascript
复制
**teneo.mapping.also_map_as_class=true
teneo.mapping.set_proxy=true
teneo.mapping.mapping_file_name=/lazy.hbm.xml**

映射文件( lazy.hbm.xml)

代码语言:javascript
复制
<class name="EnvironmentImpl" entity-name="**Environment**" abstract="false" lazy="true" discriminator-value="Environment" table="`ENVIRONMENT`" proxy="Environment">
    <meta attribute="eclassName">Environment</meta>

    <property name="name" lazy="false" insert="true" update="true" not-null="true" unique="false" type="java.lang.String">
        <column not-null="true" unique="false" name="`NAME`"/>
    </property>

    <property name="description" lazy="false" insert="true" update="true" not-null="false" unique="false" type="java.lang.String">
        <column not-null="false" unique="false" name="`DESCRIPTION`" length="512"/>
    </property>

    <property name="contact" lazy="false" insert="true" update="true" not-null="false" unique="false" type="java.lang.String">
        <column not-null="false" unique="false" name="`CONTACT`"/>
    </property>

    <many-to-one  name="rootAppFolder" entity-name="ApplicationFolder" lazy="proxy" cascade="all" foreign-key="ENVIRONMENT_ROOTAPPFOLDER" insert="true" update="true" not-null="false" unique="true">
        <column not-null="false" unique="false" name="`APPLICATINFLDER_RTAPPFOLDER_ID`"/>
    </many-to-one>

    <many-to-one name="serviceVirtualization" entity-name="ServiceVirtualization" lazy="proxy" cascade="all" foreign-key="ENVIRNMENT_SERVICEVIRTALIZATIN" insert="true" update="true" not-null="false">
        <column not-null="false" unique="false" name="`SRVCVRTLZTN_SRVICVIRTLIZTIN_ID`"/>
    </many-to-one>
</class>

As you can see class Environment has 2 many-to-one's with names ApplicationFolder and serviceVirtualization.

代码语言:javascript
复制
for a HQL query like -  from Environment where name = :name


    Which internally triggers 3 queries  
    Query1 : Environment ( this is right)

    Query2 : ApplicationFolder ( wrong.lazy loading should not.)

    Query 3 : serviceVirtualization ( wrong.lazy loading should not.)



            DEBUG - select environmen0_."NAME" as NAME4_31_, environmen0_."DESCRIPTION" as DESCRIPT5_31_, environmen0_."CONTACT" as CONTACT6_31_, environmen0_."APPLICATINFLDER_RTAPPFOLDER_ID" as APPLICAT7_31_, environmen0_."SRVCVRTLZTN_SRVICVIRTLIZTIN_ID" as SRVCVRTL8_31_ from "ENVIRONMENT" environmen0_ where environmen0_."NAME"=?

            DEBUG - select applicatio0_.e_id as e1_43_0_, applicatio0_.version_ as version3_43_0_, applicatio0_."NAME" as NAME4_43_0_, applicatio0_."ENVIRONMENT_ENV_E_ID" as ENVIRONM5_43_0_ as APPLICAT8_43_0_ from "APPLICATIONFOLDER" applicatio0_ where applicatio0_.e_id=?

            DEBUG - select servicevir0_.e_id as e1_35_0_, servicevir0_.version_ as version3_35_0_, servicevir0_.econtainer_class as econtainer4_35_0_, servicevir0_.e_container as e5_35_0_, servicevir0_.e_container_featureid as e6_35_0_ from "SERVICEVIRTUALIZATION" servicevir0_ where servicevir0_.e_id=?

到目前为止我尝试了什么方法1)设置lazy="no-proxy“,没有看到任何查询数量的变化。

2)设置not-found=“异常”。

3)outer-join = "auto“

有没有人能给我一个解决方案,来减少这两个额外的查询因为渴望的多对一关系而被解雇?

请注意多对一上的外键关系。

EN

回答 1

Stack Overflow用户

回答已采纳

发布于 2012-04-07 19:33:53

默认情况下,lazy为true。试着摆脱lazy="proxy"

懒惰不工作的原因:

  • 由于没有默认的构造函数或最终方法而无法代理被引用的类型时
  • 被引用的类型被映射为
票数 3
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页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/10032780

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