Hibernate 冬眠和H2“;引用完整性约束冲突“;对于单域双向映射
所以我有两个简单的豆子——胖子和汉堡包。现在,出于我不知道的原因,我不仅需要能够查找某人吃过的所有汉堡,还需要能够查找谁吃了哪个汉堡。进入密码 FatKid.javaHibernate 冬眠和H2“;引用完整性约束冲突“;对于单域双向映射,hibernate,foreign-keys,one-to-many,h2,bidirectional,Hibernate,Foreign Keys,One To Many,H2,Bidirectional,所以我有两个简单的豆子——胖子和汉堡包。现在,出于我不知道的原因,我不仅需要能够查找某人吃过的所有汉堡,还需要能够查找谁吃了哪个汉堡。进入密码 FatKid.java import java.util.List; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue
import java.util.List;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Table;
@Table
@Entity
public class FatKid {
private int id;
private String name;
private List<Hamburger> hamburgers;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "FATKID_ID")
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Column
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name="HAMBURGER_ID")
public List<Hamburger> getHamburgers() {
return hamburgers;
}
public void setHamburgers(List<Hamburger> hamburgers) {
this.hamburgers = hamburgers;
}
}
hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">org.h2.Driver</property>
<property name="hibernate.connection.url">jdbc:h2:~/routesetting</property>
<property name="hibernate.dialect">org.hibernate.dialect.H2Dialect</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">create-drop</property>
<mapping class="FatKid" />
<mapping class="Hamburger" />
</session-factory>
</hibernate-configuration>
因此,当我运行代码时,我最终得到了输出(以及截断的堆栈跟踪)
所以第一个汉堡包被保存了下来,但是第二个汉堡包爆炸了。两人都应该能够使用胖子的id作为外键,但似乎不起作用。如有任何见解,将不胜感激
谢谢,
凯文我觉得你的映射很奇怪。在关系的两侧都有一个@JoinColumn,每个都指向另一个表的主键。那似乎不是一对夫妻的关系 你的前女友应该告诉关系的主人:
@OneToMany(cascade = CascadeType.ALL, mappedBy = "whoDoneAteMe")
public List<Hamburger> getHamburgers() {
return hamburgers;
}
您也可以进一步优化代码。由于您的FatKid对象知道Hamburger对象,并且您已经配置了级联,因此您可以执行以下操作:
session.beginTransaction();
FatKid fk = new FatKid();
fk.setName("Darrell");
Hamburger hamburger_1 = new Hamburger();
hamburger_1.setDescription("Juicy quarter pounder with cheese");
hamburger_1.setWhoDoneAteMe(fk);
fk.getHamburgers().add(hamburger1);
Hamburger hamburger_2 = new Hamburger();
hamburger_2.setDescription("Ground buffalo burger topped with bacon and a sunny-side egg");
hamburger_2.setWhoDoneAteMe(fk);
fk.getHamburgers().add(hamburger2);
session.save(fk);
session.getTransaction().commit();
sessionFactory.close();
上述代码只需一次提交操作,就可以在一个事务中保存完整的对象图。非常感谢,删除了额外的@JoinColumn并添加了mappedBy,这一切都很顺利。
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class OmNom {
private static final SessionFactory sessionFactory = buildSessionFactory();
public static void main(String[] args) {
Session session = sessionFactory.openSession();
session.beginTransaction();
FatKid fk = new FatKid();
fk.setName("Darrell");
session.save(fk);
session.getTransaction().commit();
session.beginTransaction();
Hamburger hamburger_1 = new Hamburger();
hamburger_1.setDescription("Juicy quarter pounder with cheese");
hamburger_1.setWhoDoneAteMe(fk);
session.save(hamburger_1);
session.getTransaction().commit();
session.beginTransaction();
Hamburger hamburger_2 = new Hamburger();
hamburger_2.setDescription("Ground buffalo burger topped with bacon and a sunny-side egg");
hamburger_2.setWhoDoneAteMe(fk);
session.save(hamburger_2);
session.getTransaction().commit();
sessionFactory.close();
}
private static SessionFactory buildSessionFactory() {
try {
// Create the SessionFactory from hibernate.cfg.xml
return new Configuration().configure().buildSessionFactory();
}
catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
throw new ExceptionInInitializerError(ex);
}
}
}
Hibernate: insert into FatKid (FATKID_ID, name) values (null, ?)
Hibernate: insert into Hamburger (HAMBURGER_ID, description, FATKID_ID) values (null, ?, ?)
Hibernate: insert into Hamburger (HAMBURGER_ID, description, FATKID_ID) values (null, ?, ?)
Exception in thread "main" org.hibernate.exception.ConstraintViolationException: could not insert: [Hamburger]
...
Caused by: org.h2.jdbc.JdbcSQLException: Referential integrity constraint violation: "FK43797FE95067143: PUBLIC.HAMBURGER FOREIGN KEY(HAMBURGER_ID) REFERENCES PUBLIC.FATKID(FATKID_ID)"; SQL statement:
insert into Hamburger (HAMBURGER_ID, description, FATKID_ID) values (null, ?, ?) [23506-160]
...
@OneToMany(cascade = CascadeType.ALL, mappedBy = "whoDoneAteMe")
public List<Hamburger> getHamburgers() {
return hamburgers;
}
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "fatkid_id")
public FatKid getWhoDoneAteMe() {
return whoDoneAteMe;
}
session.beginTransaction();
FatKid fk = new FatKid();
fk.setName("Darrell");
Hamburger hamburger_1 = new Hamburger();
hamburger_1.setDescription("Juicy quarter pounder with cheese");
hamburger_1.setWhoDoneAteMe(fk);
fk.getHamburgers().add(hamburger1);
Hamburger hamburger_2 = new Hamburger();
hamburger_2.setDescription("Ground buffalo burger topped with bacon and a sunny-side egg");
hamburger_2.setWhoDoneAteMe(fk);
fk.getHamburgers().add(hamburger2);
session.save(fk);
session.getTransaction().commit();
sessionFactory.close();