我正在尝试建立一个小的Hibernate工作样本,该样本在这里找到。但是,当我运行代码时,出现以下错误
Exception in thread "main" org.hibernate.exception.SQLGrammarException: could not insert: [com.sample.Person] at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:92) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:64) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2345) at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2852) at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273) at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:320) at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203) at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129) at ..... Caused by: org.postgresql.util.PSQLException: ERROR: relation "person" does not exist Position: 13 at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2102) at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1835) at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257) at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:500) at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:388) at org.postgresql.jdbc2.AbstractJdbc2Statement.executeUpdate(AbstractJdbc2Statement.java:334) at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:94) at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57) ... 23 more
但是我已经在数据库中有了一个名为“ person”的表,这是我修改后的hibernate.cfg.xml
<!-- hibernate dialect --> <property name="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</property> <property name="hibernate.connection.driver_class">org.postgresql.Driver</property> <property name="hibernate.connection.url">jdbc:postgresql://localhost/testDB</property> <property name="hibernate.connection.username">postgres</property> <property name="hibernate.connection.password"></property> <property name="hibernate.show.sql" ></property> <property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property> <!-- Automatic schema creation (begin) === --> <property name="hibernate.hbm2ddl.auto">create</property> <!-- Simple memory-only cache --> <property name="hibernate.cache.provider_class">org.hibernate.cache.HashtableCacheProvider</property> <!-- Enable Hibernate's automatic session context management --> <property name="current_session_context_class">thread</property> <!-- ############################################ --> <!-- # mapping files with external dependencies # --> <!-- ############################################ --> <mapping resource="com/sample/Person.hbm.xml" /> </session-factory>
谁能指出我在做什么错,那太好了,因为这是我第一次在Hibernate中尝试。谢谢!
编辑:Person.hbm.xml
<class name="com.sample.Person" table="person"> <id name="id" column="ID"> <generator class="native" /> </id> <property name="name"> <column name="NAME" length="16" not-null="true" /> </property> <property name="surname"> <column name="SURNAME" length="16" not-null="true" /> </property> <property name="address"> <column name="ADDRESS" length="16" not-null="true" /> </property> </class>
EDIT-II:日志文件(Postgresql.log)的内容
2012-02-13 09:23:25 IST LOG: database system was shut down at 2012-02-10 18:14:57 IST 2012-02-13 09:23:25 IST FATAL: the database system is starting up 2012-02-13 09:23:33 IST LOG: database system is ready to accept connections 2012-02-13 09:23:38 IST LOG: autovacuum launcher started 2012-02-13 09:46:01 IST ERROR: syntax error at or near "auto_increment" at character 41 2012-02-13 09:46:01 IST STATEMENT: create table person (ID bigint not null auto_increment, NAME varchar(16) not null, SURNAME varchar(16) not null, ADDRESS varchar(16) not null, primary key (ID)) type=InnoDB 2012-02-13 09:46:01 IST ERROR: relation "person" does not exist at character 13 2012-02-13 09:46:01 IST STATEMENT: insert into person (NAME, SURNAME, ADDRESS) values ($1, $2, $3) RETURNING * 2012-02-13 09:46:01 IST LOG: could not receive data from client: No connection could be made because the target machine actively refused it. 2012-02-13 09:46:01 IST LOG: unexpected EOF on client connection 2012-02-13 09:48:15 IST ERROR: syntax error at or near "auto_increment" at character 41 2012-02-13 09:48:15 IST STATEMENT: create table person (ID bigint not null auto_increment, NAME varchar(16) not null, SURNAME varchar(16) not null, ADDRESS varchar(16) not null, primary key (ID)) type=InnoDB 2012-02-13 09:48:15 IST ERROR: relation "person" does not exist at character 13 2012-02-13 09:48:15 IST STATEMENT: insert into person (NAME, SURNAME, ADDRESS) values ($1, $2, $3) RETURNING * 2012-02-13 09:48:15 IST LOG: could not receive data from client: No connection could be made because the target machine actively refused it. 2012-02-13 09:48:15 IST LOG: unexpected EOF on client connection
更新 :我只是注意到一些奇怪的事情,我在数据库中创建了关系,然后运行这段代码,只是看到该表被删除了,因为当我运行此代码时,该表消失了。知道为什么会这样吗?
我通过修改hibernate.cfg.xml中的以下属性解决了该错误
<property name="hibernate.hbm2ddl.auto">validate</property>
之前,每次我运行该程序时,该表都会被删除,但现在却没有,因为hibernate只验证架构,而不会影响对其的更改。