java – HibernateJPAVendorAdapter和JPAProperty中的属性之间的

<!-- Configure JPA Implementation -->
<bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
      <property name="database" value="${jpa.database}" />
      <property name="showSql" value="${jpa.showSql}" />
      <property name="databasePlatform" value="${jpa.dialect}" />
      <property name="generateDdl" value="${jpa.generateDdl}" />
</bean>

<!-- Create the JPA EntityManagerFactory -->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
      <property name="dataSource" ref="dataSource"/>
      <property name="jpaVendorAdapter" ref="jpaVendorAdapter"/>
      <property name="packagesToScan">
           <list>
               <value>com.proyectofinal.model</value>
           </list>
      </property>
      <property name="jpaProperty">  
           <props>  
               <entry key="hibernate.cache.use_second_level_cache" value="true"/>  
               <entry key="hibernate.cache.use_query_cache" value="true"/>  
               <entry key="hibernate.cache.provider_class" value="net.sf.ehcache.hibernate.SingletonEhCacheProvider"/>  
               <entry key="hibernate.show_sql" value="true" />  
               <entry key="hibernate.use_sql_comments" value="false" />  
               <entry key="hibernate.format_sql" value="true" />  
               <entry key="hibernate.dialect" value="org.hibernate.dialect.MYSQLDialect" />  
               <entry key="hibernate.temp.use_jdbc_metadata_defaults" value="false"/>  
           </props>  
      </property>  
</bean>

我的问题是：

>是否有必要在两个地方定义show_sql或dialect等属性？
>哪一个优先于另一个？
>哪个地方更适合定义它？

提前致谢