Java <；属性名称=“属性名称”；hibernate.hbm2ddl.auto&燃气轮机；更新</房地产>；在oracle数据库和mysql中不起作用

这是我的hibernate.cfg.xml文件，hbm2ddl.auto属性设置为update，如果数据库中不存在表，则不会创建表。hbm2ddl.auto create工作正常

五十

        <property name="hibernate.connection.driver_class">oracle.jdbc.OracleDriver</property> 
            <property name="hibernate.connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property> 
            <property name="hibernate.connection.username">root</property> <property 
            name="hibernate.connection.password">root</property> <property name="hibernate.connection.pool_size">1</property> 
            <property name="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</property>
<property name="hibernate.c3p0.min_size">3</property>
        <property name="hibernate.c3p0.max_size">3</property>
        <property name="hibernate.c3p0.max_statements">50</property>
        <property name="connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
        <property name="hibernate.c3p0.timeout">1800</property>
        <property name="hibernate.c3p0.acquireRetryDelay">1000</property>
        <property name="hibernate.c3p0.acquireRetryAttempts">60</property>

        <property name="hibernate.c3p0.acquire_increment">3</property>
        <property name="hibernate.c3p0.idle_test_period">14400</property>
        <property name="hibernate.c3p0.preferredTestQuery">select 1</property>

        <property name="cache.use_second_level_cache">false</property>
        <property name="cache.provider_class">org.hibernate.cache.EhCacheProvider</property>
        <property name="hibernate.cache.region.factory_class">net.sf.ehcache.hibernate.SingletonEhCacheRegionFactory</property>
        <property name="hibernate.cache.use_query_cache">false</property>
        <property name="current_session_context_class">thread</property>

        <property name="show_sql">true</property>
         <property name="hibernate.hbm2ddl.auto">update</property>
         <mapping resource="STUDENT.hbm.xml" /> 
    </session-factory>
</hibernate-configuration>

oracle.jdbc.OracleDriver
jdbc:oracle:thin:@localhost:1521:orcl
根1
org.hibernate.dialen.oracle10galent
3.
3.
50
org.hibernate.connection.C3P0ConnectionProvider
1800
1000
60
3.
14400
选择1
假的
org.hibernate.cache.EhCacheProvider
net.sf.ehcache.hibernate.SingletonEhCacheRegionFactory
假的
线
真的
更新

使用Oracledb的某些hibernate版本中的更新功能存在一些已知问题，请尝试使用5.0版或5.1.4版之后的版本

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您使用的是哪个版本的hibernate？