How to use Hibernate to generate a DDL script from your Play! Framework project

Ok, so you have been using the hibernate property name=”hibernate.hbm2ddl.auto” value=”update” to continuously update your database schema, but now you need a complete DDL script?

Use this method from you Global Class onStart to export the DDL scripts.  Just give it the package name (with path) of your Entities as well as a file name:

public void onStart(Application app) {
        exportDatabaseSchema("models", "create_tables.sql");
    }

    public void exportDatabaseSchema(String packageName, String scriptFilename) {

        final Configuration configuration = new Configuration();
        final Reflections reflections = new Reflections(packageName);
        final Set<Class<?>> classes = reflections.getTypesAnnotatedWith(Entity.class);
        // iterate all Entity classes in the package indicated by the name
        for (final Class<?> clazz : classes) {
            configuration.addAnnotatedClass(clazz);
        }
        configuration.setProperty("hibernate.dialect", "org.hibernate.dialect.PostgreSQL9Dialect");

        SchemaExport schema = new SchemaExport(configuration);
        schema.setOutputFile(scriptFilename);
        schema.setDelimiter(";");
        schema.execute(Target.SCRIPT, SchemaExport.Type.CREATE );  // just export the create statements in the script
    }

That is it!

Thanks to @MonCalamari for answering my Question on Stackoverflow here.

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