hibernate框架cascade和inverse的区别（十六）

1. cascade用来级联操作（保存、修改和删除）

2. inverse用来维护外键的

一、只配置cascade="save-update"

1.1 配置

只在customer.hbm.xml中配置cascade="save-update"

1.2 测试代码

/**
* cascade和inverse的区别
*/
@Test
public void run12() {
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();

// 级联保存
Customer c1 = new Customer();
c1.setCust_name("meimei");

// 创建2个联系人
Linkman l1 = new Linkman();
l1.setLkm_name("xiongda");
Linkman l2 = new Linkman();
l2.setLkm_name("xionger");

// 单向关联
c1.getLinkmans().add(l1);
c1.getLinkmans().add(l2);

// 保存数据
session.save(c1);

tx.commit();
}

1.3 运行效果

customer表中有一条数据

linkman表中有两条数据，并且有外键

看sql：

log4j:WARN No appenders could be found for logger (org.jboss.logging).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Hibernate:
insert
into
cst_customer
(cust_name, cust_user_id, cust_create_id, cust_source, cust_industry, cust_level, cust_linkman, cust_phone, cust_mobile)
values
(?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate:
insert
into
cst_linkman
(lkm_name, lkm_gender, lkm_phone, lkm_mobile, lkm_email, lkm_qq, lkm_position, lkm_memo, lkm_cust_id)
values
(?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate:
insert
into
cst_linkman
(lkm_name, lkm_gender, lkm_phone, lkm_mobile, lkm_email, lkm_qq, lkm_position, lkm_memo, lkm_cust_id)
values
(?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate:
update
cst_linkman
set
lkm_cust_id=?
where
lkm_id=?
Hibernate:
update
cst_linkman
set
lkm_cust_id=?
where
lkm_id=?

二、配置inverse="true"

2.1 配置

2.2 测试代码

/**
* cascade和inverse的区别
*/
@Test
public void run12() {
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();

// 级联保存
Customer c1 = new Customer();
c1.setCust_name("meimei");

// 创建2个联系人
Linkman l1 = new Linkman();
l1.setLkm_name("xiongda");
Linkman l2 = new Linkman();
l2.setLkm_name("xionger");

// 单向关联
c1.getLinkmans().add(l1);
c1.getLinkmans().add(l2);

// 保存数据
session.save(c1);

tx.commit();
}

2.3 运行效果

linkman里面没有外键了

看sql：

log4j:WARN No appenders could be found for logger (org.jboss.logging).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Hibernate:
insert
into
cst_customer
(cust_name, cust_user_id, cust_create_id, cust_source, cust_industry, cust_level, cust_linkman, cust_phone, cust_mobile)
values
(?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate:
insert
into
cst_linkman
(lkm_name, lkm_gender, lkm_phone, lkm_mobile, lkm_email, lkm_qq, lkm_position, lkm_memo, lkm_cust_id)
values
(?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate:
insert
into
cst_linkman
(lkm_name, lkm_gender, lkm_phone, lkm_mobile, lkm_email, lkm_qq, lkm_position, lkm_memo, lkm_cust_id)
values
(?, ?, ?, ?, ?, ?, ?, ?, ?)

三、最终方案

在一方配置inverse="true"，在多方配置cascade="save-update"

3.1 配置

3.2 测试代码

/**
* save的最终方案，开发中就这么用
*/
@Test
public void run13() {
Session session = HibernateUtils.getCurrentSession();
Transaction tx = session.beginTransaction();

// 级联保存
Customer c1 = new Customer();
c1.setCust_name("meimei");

// 创建2个联系人
Linkman l1 = new Linkman();
l1.setLkm_name("xiongda");
Linkman l2 = new Linkman();
l2.setLkm_name("xionger");

// 单向关联
l1.setCustomer(c1);
l2.setCustomer(c1);

// 保存数据
session.save(l1);
session.save(l2);

tx.commit();
}

3.3 运行效果

看sql：

log4j:WARN No appenders could be found for logger (org.jboss.logging).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Hibernate:
insert
into
cst_customer
(cust_name, cust_user_id, cust_create_id, cust_source, cust_industry, cust_level, cust_linkman, cust_phone, cust_mobile)
values
(?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate:
insert
into
cst_linkman
(lkm_name, lkm_gender, lkm_phone, lkm_mobile, lkm_email, lkm_qq, lkm_position, lkm_memo, lkm_cust_id)
values
(?, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate:
insert
into
cst_linkman
(lkm_name, lkm_gender, lkm_phone, lkm_mobile, lkm_email, lkm_qq, lkm_position, lkm_memo, lkm_cust_id)
values
(?, ?, ?, ?, ?, ?, ?, ?, ?)
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