Hibernate 5. Generate SQL DDL into file

Question

I tried using this class:

Hibernate/JPA: Check generated sql before updating DB Schema (like .NET EF migrations)

I have the following code:

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Answer 1

Apparently the Configuration class can not be used. We must use the MetadataSources class to add the annotated classes.

private void generate(Dialect dialect, String directory, String[] packagesName) throws Exception {

    MetadataSources metadata = new MetadataSources(
            new StandardServiceRegistryBuilder()
                    .applySetting("hibernate.dialect", dialect.getDialectClass())
                    .build());

    for (String packageName : packagesName) {
        log.info("packageName: " + packageName);
        for (Class clazz : getClasses(packageName)) {
            log.info("Class: " + clazz);
            metadata.addAnnotatedClass(clazz);
        }
    }

    SchemaExport export = new SchemaExport(
            (MetadataImplementor) metadata.buildMetadata()
    );

    export.setDelimiter(";");
    export.setOutputFile(directory + "ddl_" + dialect.name().toLowerCase() + ".sql");
    export.setFormat(true);
    export.execute(true, false, false, false);
}

Answer 2

I wrote a class for generating sql script depends on packages with entites.

Used version of hibernate is '5.3.7.Final'

public final class HibernateExporter {

    private static final Logger LOG = LoggerFactory.getLogger(HibernateExporter.class);
    private static final String OUTPUT_FILE = "schema.sql";
    private static final String DIALECT = "org.hibernate.dialect.H2Dialect";

    private List<String> entityPackages;

    private HibernateExporter(List<String> entityPackages) {
        this.entityPackages = entityPackages;
    }

    public static void main(String[] args) {
        final List<String> entityPackages = Collections.singletonList("pakage.with.entites");

        HibernateExporter exporter = new HibernateExporter(entityPackages);
        exporter.export();
    }

    private void export() {
        SchemaExport export = new SchemaExport();
        export.setOutputFile(OUTPUT_FILE);
        export.setFormat(true);
        export.setDelimiter(";");
        EnumSet<TargetType> types = EnumSet.of(TargetType.SCRIPT);
        Metadata metadata = createMetadataSources().buildMetadata();
        export.execute(types, Action.CREATE, metadata);
    }

    private MetadataSources createMetadataSources() {
        MetadataSources metadata = new MetadataSources(
                new StandardServiceRegistryBuilder()
                        .applySetting("hibernate.dialect", DIALECT)
                        .build());

        for (String entityPackage : entityPackages) {
            final Reflections reflections = new Reflections(entityPackage);
            for (Class<?> cl : reflections.getTypesAnnotatedWith(MappedSuperclass.class)) {
                metadata.addAnnotatedClass(cl);
                LOG.info(String.format("Mapped = %s", cl.getName()));
            }
            for (Class<?> cl : reflections.getTypesAnnotatedWith(Entity.class)) {
                metadata.addAnnotatedClass(cl);
                LOG.info(String.format("Mapped = %s", cl.getName()));
            }
        }
        return metadata;
    }
}

Answer 3

The solution of felix don't work anymore on hibernate 5.2 here is a version which is compatible

private void generate(Class dialect, String directory, String... packagesName) throws Exception {

    MetadataSources metadata = new MetadataSources(
            new StandardServiceRegistryBuilder()
                    .applySetting("hibernate.dialect", dialect.getName())
                    .build());

    for (String packageName : packagesName) {
        LOG.info("packageName: " + packageName);
        for (Class clazz : getClasses(packageName)) {
            LOG.info("Class: " + clazz);
            metadata.addAnnotatedClass(clazz);
        }
    }

    MetadataImplementor metadataImplementor = (MetadataImplementor) metadata.buildMetadata();
    SchemaExport export = new SchemaExport();

    export.setDelimiter(";");
    String filename = directory + "ddl_" + dialect.getSimpleName().toLowerCase() + ".sql";
    export.setOutputFile(filename);
    export.setFormat(true);

    //can change the output here
    EnumSet<TargetType> enumSet = EnumSet.of(TargetType.STDOUT);
    export.execute(enumSet, SchemaExport.Action.CREATE, metadataImplementor);
}

Answer 4

Normally tools that dumps the JPA schema are based on SchemaExport tool, which reads only the static metadata.

There is a Maven/Gradle plugin https://github.com/Devskiller/jpa2ddl which generates the JPA schema. In includes all properties, namings strategies, user types, etc.

You can also use it to generate automated schema migrations for Flyway.