How to create ddl file with spring data and java based configuration?

Question

I have my spring data JPA configuration up and running. I'd like to get a ddl sql file from my annotated entities.

I know this has been asked many times. But I could not find something usefull explaing how to do this with java based spring configuration.

This is my JPA set-up:

@Bean(name = BEAN_ENTITY_MANAGER_FACTORY)
public EntityManagerFactory entityManagerFactory() {
    LocalContainerEntityManagerFactoryBean em = createLocalContainerEntityManagerFactoryBean();
    em.setDataSource(dataSource());
    em.setJpaVendorAdapter(jpaVendorAdapter());
    em.setPersistenceUnitName(getPersistenceUnitName());
    em.setPackagesToScan(getPackagesToScan());
    processOptionalProperty(Environment.HBM2DDL_AUTO, em);
    processOptionalProperty(HIBERNATE_JDBC_BATCH_SIZE, em);
    processOptionalProperty(EHCACHE_CONFIGURATIONRESOURCENAME_PROPERTY, em);
    em.afterPropertiesSet();
    return em.getObject();
}

@Bean(name = BEAN_HIBERNATE_JPA_VENDOR_ADAPTER)
public HibernateJpaVendorAdapter jpaVendorAdapter() {
    HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();
    adapter.setShowSql(Boolean.parseBoolean(getPropertyValue(HIBERNATE_SHOW_SQL_PROPERTY)));
    adapter.setDatabasePlatform(getPropertyValue(HIBERNATE_DATABASE_PLATFORM_PROPERTY));
    adapter.setGenerateDdl(true);
    return adapter;
}

The hbm2ddl is set like this:

hibernate.hbm2ddl.auto=create

This configuration creates the necessary database tables at application start-up. How can I get an sql script containing all the ddl commands to set-up the DB?

Answer 1

After a lot of googling and try and error this is the solution I found.

To generate a ddl script you need the maven hibernate3:hbm2ddl plugin. To get the plugin I added this to my pom.xml:

        <plugin>
            <!-- run "mvn hibernate3:hbm2ddl" to generate a schema -->
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>hibernate3-maven-plugin</artifactId>
            <version>2.2</version>
            <configuration>
                <components>
                    <component>
                        <name>hbm2ddl</name>
                        <implementation>jpaconfiguration</implementation>
                    </component>
                </components>
                <componentProperties>
                    <persistenceunit>eai</persistenceunit>
                    <outputfilename>ddl-file.sql</outputfilename>
                    <drop>false</drop>
                    <create>true</create>
                    <export>false</export>
                    <format>true</format>
                </componentProperties>
            </configuration>
            <dependencies>
                <dependency>
                    <groupId>org.hibernate.javax.persistence</groupId>
                    <artifactId>hibernate-jpa-2.0-api</artifactId>
                    <version>1.0.0.Final</version>
                </dependency>
            </dependencies>
        </plugin>

The nasty bit to find was the the dependency section. Thanks to this blog post to point this out.

The second thing I got stuck was the persistence unit name. This is configured by placing a file called persistence.xml into your META-INF directory.

<?xml version="1.0" encoding="UTF-8"?>

<persistence version="1.0"
    xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
         http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">

    <persistence-unit name="eai">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <properties>

            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLInnoDBDialect" />
            <!-- other properties ... -->
        </properties>
    </persistence-unit>
</persistence>

This file also contains the hibernate dialect. This is important to get the sql that makes your db happy.