Question

I am trying to create an application bootstrap that will drop all the tables in the application if they exist and then intialise them with fresh data.

I have created a Spring Context that loads the datasource context – however I dont know how to override the initialisation of the datasource such that the behaviour can be customised depending on how the datasource is loaded. So.. using Hibernate as my JPA implementation..

If the datasource is loaded from the application – then I would like the schemas to update:

    <persistence-unit name="myDB" transaction-type="RESOURCE_LOCAL">
    <properties>
        <property name="hibernate.hbm2ddl.auto" value="update"/>
    </properties>
</persistence-unit>

If the datasource is loaded from the bootstrap – then I need to overload this behaviour somehow so that the database is always created from scratch before fresh data is loaded:

    <persistence-unit name="myDB" transaction-type="RESOURCE_LOCAL">
    <properties>
        <property name="hibernate.hbm2ddl.auto" value="create"/>
    </properties>
</persistence-unit>

The approach I have been taking doesn’t work as I would load the datasource using the ‘update’ setting and then drop the tables if they exist before attempting to load new data. However – the tables no longer exist for writing data !

Thanks in advance

Simon

Answer 1

You can pass JPA properties from Spring configuration instead of persistance.xml and use placeholder that can be configured by PlaceholderConfigurer (possibly system-properties=”OVERRIDE”), or Spring profiles (since 3.1) or using Maven filtering:

<util:map id="jpaPropertyMap" key-type="java.lang.String" value-type="java.lang.Object">
    <entry key="hibernate.hbm2ddl.auto" value="${database.ddl.mode}" />
</util:map>

<bean id="managementEntityManagerFactory"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
    p:dataSource-ref="dataSource"
    p:jpaPropertyMap-ref="jpaPropertyMap" />