我目前正在学习休眠方式，并试图了解这种关系。我正在研究图书馆数据库的示例。我有3张桌子：
客户 书 订购
在“客户”和“书”中，有诸如客户名称，书名等信息。我想在订单表中建立一个客户订购哪本书的关系。所以我写了课：
@Entity
public class Order
{
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
private Date date;
private String status;
@OneToMany
private List<Book> books;
@OneToOne
private Customer customer;
//Getters, setters, constructors, etc...
如上所示，我实现了关系：
@OneToMany-因为一个订单我可以订购很多本书。
@OneToOne-因为在一个订单中我只能有一位订购书籍的客户。
下面您可以看到我的测试课：
public class Test
{
public static void main (String args[])
{
DBManager dbManager = new DBManager();
List <Book> books = new ArrayList<>();
books.addAll(Arrays.asList(
new Book(1,"Hobbit","JRR",10.2),//isbn,title,autor name, price
new Book(2,"Witcher","Andrzej",20.3),
new Book(3,"LOTR1","JRR",19.99),
new Book(4,"LOTR2","JRR",29.99)));
dbManager.addEntities(books);
List<Customer> customers = new ArrayList<>();
customers.addAll(Arrays.asList(
new Customer("A","M","W"),//name, surname, city
new Customer("K", "S", "Z"),
new Customer("P","Z","Z")
));
dbManager.addEntities(customers);
dbManager.addEntity(new Order(Date.valueOf("2019-06-01"),"nowy",books.subList(1,2), customers.get(0)));
}
}
DBManager是一个简单的Util类：
public class DBManager
{
private final SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
public <T> void addEntity(T t)
{
Session session=sessionFactory.openSession();
session.beginTransaction();
session.save(t);
session.getTransaction().commit();
session.close();
}
public <T> void addEntities(List<T> entities)
{
Session session=sessionFactory.openSession();
session.beginTransaction();
entities.forEach(session::save);
session.getTransaction().commit();
session.close();
}
}
运行测试时，我遇到以下异常：
cze 01, 2019 2:46:32 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {5.4.2.Final}
cze 01, 2019 2:46:33 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
cze 01, 2019 2:46:34 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl configure
WARN: HHH10001002: Using Hibernate built-in connection pool (not for production use!)
cze 01, 2019 2:46:34 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001005: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/hibernatedb]
cze 01, 2019 2:46:34 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001001: Connection properties: {password=****, user=root}
cze 01, 2019 2:46:34 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl buildCreator
INFO: HHH10001003: Autocommit mode: false
cze 01, 2019 2:46:34 PM org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl$PooledConnections <init>
INFO: HHH000115: Hibernate connection pool size: 100 (min=1)
cze 01, 2019 2:46:34 PM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.MySQL5Dialect
cze 01, 2019 2:46:35 PM org.hibernate.resource.transaction.backend.jdbc.internal.DdlTransactionIsolatorNonJtaImpl getIsolatedConnection
INFO: HHH10001501: Connection obtained from JdbcConnectionAccess [org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess@5fa23c] for (non-JTA) DDL execution was not in auto-commit mode; the Connection 'local transaction' will be committed and the Connection will be set into auto-commit mode.
Hibernate: create table Order (id bigint not null auto_increment, date date, status varchar(255), customer_id bigint, primary key (id)) engine=MyISAM
cze 01, 2019 2:46:35 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "create table Order (id bigint not null auto_increment, date date, status varchar(255), customer_id bigint, primary key (id)) engine=MyISAM" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "create table Order (id bigint not null auto_increment, date date, status varchar(255), customer_id bigint, primary key (id)) engine=MyISAM" via JDBC Statement
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.createTable(AbstractSchemaMigrator.java:277)
at org.hibernate.tool.schema.internal.GroupedSchemaMigratorImpl.performTablesMigration(GroupedSchemaMigratorImpl.java:71)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:207)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:309)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:462)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
at HibernateUtil.buildSessionFactory(HibernateUtil.java:23)
at HibernateUtil.<clinit>(HibernateUtil.java:8)
at DBManager.<init>(DBManager.java:9)
at Test.main(Test.java:11)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'Order (id bigint not null auto_increment, date date, status varchar(255), custom' at line 1
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.Util.getInstance(Util.java:387)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:942)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3966)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3902)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2526)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2673)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2545)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2503)
at com.mysql.jdbc.StatementImpl.executeInternal(StatementImpl.java:839)
at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:739)
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54)
... 15 more
Hibernate: alter table Order add constraint FKjd3x2xgs94mmspkead2wpjhgs foreign key (customer_id) references Customer (id)
cze 01, 2019 2:46:35 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "alter table Order add constraint FKjd3x2xgs94mmspkead2wpjhgs foreign key (customer_id) references Customer (id)" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "alter table Order add constraint FKjd3x2xgs94mmspkead2wpjhgs foreign key (customer_id) references Customer (id)" via JDBC Statement
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applyForeignKeys(AbstractSchemaMigrator.java:433)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:249)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:309)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:462)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
at HibernateUtil.buildSessionFactory(HibernateUtil.java:23)
at HibernateUtil.<clinit>(HibernateUtil.java:8)
at DBManager.<init>(DBManager.java:9)
at Test.main(Test.java:11)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'Order add constraint FKjd3x2xgs94mmspkead2wpjhgs foreign key (customer_id) refer' at line 1
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.Util.getInstance(Util.java:387)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:942)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3966)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3902)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2526)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2673)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2545)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2503)
at com.mysql.jdbc.StatementImpl.executeInternal(StatementImpl.java:839)
at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:739)
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54)
... 14 more
Hibernate: alter table Order_Book add constraint FKh6ubcn53wu832xkdyp4bq2g4h foreign key (books_id) references Book (id)
Hibernate: alter table Order_Book add constraint FKleoto2431q8tq7ulptjuk9526 foreign key (Order_id) references Order (id)
cze 01, 2019 2:46:35 PM org.hibernate.tool.schema.internal.ExceptionHandlerLoggedImpl handleException
WARN: GenerationTarget encountered exception accepting command : Error executing DDL "alter table Order_Book add constraint FKleoto2431q8tq7ulptjuk9526 foreign key (Order_id) references Order (id)" via JDBC Statement
org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "alter table Order_Book add constraint FKleoto2431q8tq7ulptjuk9526 foreign key (Order_id) references Order (id)" via JDBC Statement
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applyForeignKeys(AbstractSchemaMigrator.java:433)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:249)
at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184)
at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73)
at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:309)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:462)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:708)
at HibernateUtil.buildSessionFactory(HibernateUtil.java:23)
at HibernateUtil.<clinit>(HibernateUtil.java:8)
at DBManager.<init>(DBManager.java:9)
at Test.main(Test.java:11)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'Order (id)' at line 1
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.Util.getInstance(Util.java:387)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:942)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3966)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3902)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2526)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2673)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2545)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2503)
at com.mysql.jdbc.StatementImpl.executeInternal(StatementImpl.java:839)
at com.mysql.jdbc.StatementImpl.execute(StatementImpl.java:739)
at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54)
... 14 more
Hibernate: insert into Book (ISBN, autorName, name, price) values (?, ?, ?, ?)
Hibernate: insert into Book (ISBN, autorName, name, price) values (?, ?, ?, ?)
Hibernate: insert into Book (ISBN, autorName, name, price) values (?, ?, ?, ?)
Hibernate: insert into Book (ISBN, autorName, name, price) values (?, ?, ?, ?)
Hibernate: insert into Customer (city, lastName, name) values (?, ?, ?)
Hibernate: insert into Customer (city, lastName, name) values (?, ?, ?)
Hibernate: insert into Customer (city, lastName, name) values (?, ?, ?)
Hibernate: insert into Order (customer_id, date, status) values (?, ?, ?)
cze 01, 2019 2:46:36 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
WARN: SQL Error: 1064, SQLState: 42000
cze 01, 2019 2:46:36 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
ERROR: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'Order (customer_id, date, status) values (16, '2019-06-01', 'nowy')' at line 1
Exception in thread "main" org.hibernate.exception.SQLGrammarException: could not execute statement
at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:63)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:113)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:99)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:178)
at org.hibernate.dialect.identity.GetGeneratedKeysDelegate.executeAndExtract(GetGeneratedKeysDelegate.java:57)
at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:42)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3079)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3673)
at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:81)
at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:645)
at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:282)
at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:263)
at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:317)
at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:332)
at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:289)
at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:196)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:127)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:192)
at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:177)
at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:713)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:705)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:700)
at DBManager.addEntity(DBManager.java:97)
at Test.main(Test.java:29)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'Order (customer_id, date, status) values (16, '2019-06-01', 'nowy')' at line 1
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
at com.mysql.jdbc.Util.getInstance(Util.java:387)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:942)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3966)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3902)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2526)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2673)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2549)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1861)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2073)
at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2009)
at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5098)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1994)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:175)
... 23 more
有人知道是什么原因吗？