问题描述
我正在尝试建立一个小型的Hibernate工作样本,该样本我找到了这里但是,当我运行代码时,出现以下错误
I'm trying to set up a small working sample of Hibernate that I found here However when I run the code I get the follwing error
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
But I already have a table by the name person in the database and here's my modified 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>
如果有人指出我在做什么错,那将是很棒的,因为这是我第一次尝试Hibernate.谢谢!
It would be great if anyone could point out what Im doing wrong, as this is my first attempt at Hibernate.Thanks!
Person.hbm.xml
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
EDIT-II: Content of the log file (Postgresql.log)
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:我只是注意到有些奇怪,我在数据库中创建了关系,然后运行了这段代码,只是看到表被删除了,因为它在运行时消失了代码;知道为什么会这样吗?
UPDATE: I just noticed something weird, I create the relation in the DB and then run this piece of code, only to see that the table gets deleted as in it just dissapears when I run this code; any idea why this happens?
推荐答案
我通过修改hibernate.cfg.xml中的以下属性来解决了该错误
I solved the error by modifying the following property in hibernate.cfg.xml
<property name="hibernate.hbm2ddl.auto">validate</property>
以前,每次我运行该程序时,该表都会被删除,但现在却没有,因为休眠只验证架构,而不会影响对其的更改.
Earlier, the table was getting deleted each time I ran the program and now it doesnt, as hibernate only validates the schema and does not affect changes to it.
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