hibernate中的set集合配置lazy="extra"

本文介绍了一种特殊的懒加载配置方式,该配置允许在不需要获取整个集合数据的情况下执行size和contains等方法,仅在真正使用时查询整个集合,从而提高效率。

摘要生成于 C知道 ,由 DeepSeek-R1 满血版支持, 前往体验 >

这种配置和配置为lazy=true是一样的,但它的好处在于调用size/contains等方法时,并不查询整个集合的数据,而是发送一条sql语句来处理,只有真正在使用时才全部去查询整个集合
<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd "> <!-- Generated 2015-4-10 11:00:59 by Hibernate Tools 4.0.0 --> <hibernate-mapping> <class name="com.xtest.models.EntityLayout" table="EntityLayout"> <id name="elSid" type="string"> <column name="el_sid" length="36"/> <generator class="org.hibernate.id.UUIDGenerator" /> </id> <many-to-one name="entityTables" class="com.xtest.models.EntityTables" fetch="select"> <column name="el_et_sid" length="36" /> </many-to-one> <property name="elName" type="string"> <column name="el_name" not-null="true" /> </property> <property name="elGroupName" type="string"> <column name="el_group_name" /> </property> <property name="elType" type="int"> <column name="el_type" not-null="true" /> </property> <property name="elStatusSid" type="string"> <column name="el_status_sid" /> </property> <property name="elDesc" type="string"> <column name="el_desc" /> </property> <set fetch="select" inverse="true" lazy="true" name="entityComposites" order-by="ecSortNo" sort="unsorted" table="EntityComposite"> <key> <column length="36" name="ec_el_sid"/> </key> <one-to-many class="com.xtest.models.EntityComposite"/> </set> <set fetch="select" inverse="true" lazy="true" name="entityLists" order-by="eldSortNo" sort="unsorted" table="EntityList"> <key> <column length="36" name="eld_el_sid"/> </key> <one-to-many class="com.xtest.models.EntityList"/> </set> <set fetch="select" inverse="true" lazy="true" name="entityForms" order-by="efdSortNo" sort="unsorted" table="EntityForm"> <key> <column length="36" name="efd_el_sid"/> </key> <one-to-many class="com.xtest.models.EntityForm"/> </set> <set fetch="select" inverse="true" lazy="true" name="entityTreeviews" order-by="etvSort" sort="unsorted" table="EntityTreeview"> <key> <column length="36" name="etv_el_sid"/> </key> <one-to-many class="com.xtest.models.EntityTreeview"/> </set> <set fetch="select" inverse="true" lazy="true" name="entityTreeviewCMenus" order-by="etvmName" sort="unsorted" table="EntityTreeviewCMenus"> <key> <column length="36" name="etvm_el_sid"/> </key> <one-to-many class="com.xtest.models.EntityTreeviewCMenus"/> </set> </class> </hibernate-mapping> 你看一下和这个有关系嘛
最新发布
07-30
评论 1
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值