Hibernate级联cascade 完整实例 及 错误解决（mysql）
最近在学习Hibernate（基于《深入浅出Hibernate》一书），在动手练习的时候，出现了一些问题，并加以解决，现将其罗列如下：
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数据库表创建：
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CREATE TABLE `t_user` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(45) default NULL, `age` int(3) default NULL, `group_id` int(11) default NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;?
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CREATE TABLE `t_passport` ( `id` int(11) NOT NULL , `serial` varchar(30) default NULL, `expiry` int(11) default NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;?
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配置文件：
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<?xml version="1.0" encoding="GB2312"?><!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"><beans><bean id="myDataSource" destroy-method="close"> <property name="driverClassName" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://localhost:3306/test" /> <property name="username" value="root" /> <property name="password" value="123" /> <property name="maxActive" value="64"/> <property name="maxIdle" value="2" /> <property name="maxWait" value="10" /> <!-- <property name="validationQuery" value="select sysdate from dual" /> --> <property name="testWhileIdle" value="true" /> <property name="timeBetweenEvictionRunsMillis" value="60000" /> <property name="minEvictableIdleTimeMillis" value="60000" /> <property name="removeAbandoned" value="true" /></bean><bean id="mySessionFactory" name="code"><?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC"-//Hibernate/Hibernate Mapping DTD//EN""http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" ><hibernate-mapping><class name="com.chinabank.b2c.hbm.TUser" table="t_user"><id name="id" column="id" type="java.lang.Integer"><generator type="java.lang.String" column="name"></property><property name="age" type="java.lang.Integer" column="age"></property><!-- --><one-to-one name="passport" outer-join="true"></one-to-one></class></hibernate-mapping>?
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<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC"-//Hibernate/Hibernate Mapping DTD//EN""http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" ><hibernate-mapping><class name="com.chinabank.b2c.hbm.TPassport" table="t_passport"><id name="id" column="id" type="java.lang.Integer"><generator type="java.lang.String" column="serial"></property><property name="expiry" type="java.lang.Integer" column="expiry"></property><one-to-one name="user" name="code">package com.chinabank.b2c.hbm;import java.io.Serializable;public class TUser implements Serializable {/** * */private static final long serialVersionUID = -1523232529237055567L;public TUser(){}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}public TPassport getPassport() {return passport;}public void setPassport(TPassport passport) {this.passport = passport;}private Integer id;private Integer age;private String name;private TPassport passport;}??
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package com.chinabank.b2c.hbm;import java.io.Serializable;public class TPassport implements Serializable {/** * */private static final long serialVersionUID = -7458971855517828094L;public TPassport(){}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getSerial() {return serial;}public void setSerial(String serial) {this.serial = serial;}public Integer getExpiry() {return expiry;}public void setExpiry(Integer expiry) {this.expiry = expiry;}public TUser getUser() {return user;}public void setUser(TUser user) {this.user = user;}private Integer id;private String serial;private Integer expiry;private TUser user;public String toString(){return this.serial+this.id+this.expiry+user.toString();}}??
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public void cascadeT(){ApplicationContext context = new ClassPathXmlApplicationContext("spring-config.xml");HibernateTransactionManager manager = (HibernateTransactionManager) context.getBean("myTransactionManager");try {Session session = manager.getSessionFactory().openSession();TUser user = new TUser();user.setAge(new Integer(20));user.setName("Carin");TPassport passport = new TPassport();passport.setSerial("PCN759386");passport.setExpiry(new Integer(20150101));// 设置关联passport.setUser(user);user.setPassport(passport);Transaction tx = session.beginTransaction();session.save(user);tx.commit();} catch (HibernateException e) {e.printStackTrace();}}??
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以上是最终代码。在此之前，曾遇到过这样几个问题：
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错误1.hibernate方言适配器配置不对。
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2012-5-22 3:22:12 net.sf.hibernate.id.TableGenerator generate严重: could not read a hi valuecom.mysql.jdbc.exceptions.MySQLSyntaxErrorException: Table 'test.hibernate_unique_key' doesn't exist
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错：<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop> 对：<prop key="hibernate.dialect">net.sf.hibernate.dialect.MySQLDialect</prop>
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错误2. 主键没有设置为自动增长
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警告: SQL Error: 1364, SQLState: HY0002012-5-22 3:27:05 net.sf.hibernate.util.JDBCExceptionReporter logExceptions严重: Field 'id' doesn't have a default valuenet.sf.hibernate.exception.GenericJDBCException: could not insert: [com.chinabank.b2c.hbm.TUser]
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`id` int(11) NOT NULL?之后加上 AUTO_INCREMENT 即：`id` int(11) NOT NULL AUTO_INCREMENT
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错误3. 错误的添加外键，画蛇添足
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警告: SQL Error: 1452, SQLState: 230002012-5-22 3:34:40 net.sf.hibernate.util.JDBCExceptionReporter logExceptions严重: Cannot add or update a child row: a foreign key constraint fails (`test`.`t_user`, CONSTRAINT `fk1` FOREIGN KEY (`id`) REFERENCES `t_passport` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION)net.sf.hibernate.exception.GenericJDBCException: could not insert: [com.chinabank.b2c.hbm.TUser]?
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去掉外键