Howto create sql files without database connection using hibernate 5

Question

In hibernate 4 I used config.generateSchemaCreationScript(dialect); to generate sql creation script files from our classes. After update to hibernate 5 (5.6.5.Final to be precise) I'm trying to create the same behavior.

Tried the following:

Configuration config = new Configuration();
for (Class<?> type : types) {
  config.addAnnotatedClass(type);
}
ServiceRegistry serviceRegistry = config.getStandardServiceRegistryBuilder().applySetting(Environment.DIALECT, MariaDBDialect.class).build();
Metadata metadata = new MetadataSources(serviceRegistry).getMetadataBuilder().build();

SchemaExport schemaExport = new SchemaExport();
schemaExport.setHaltOnError(true);
schemaExport.setFormat(true);
schemaExport.setDelimiter(";");
schemaExport.setOutputFile(new File("create.sql"));
schemaExport.createOnly(EnumSet.of(TargetType.SCRIPT), metadata);

This code gives me lots of warnings "java.sql.SQLException: No suitable driver" and "java.sql.SQLException: Connections could not be acquired from the underlying database!". It seems that creation of the metadata object already tries to create a database connection. But I don't have/want a database connection, I only want to create sql files from the database objects.

I've also tried to do schemaExport.execute(EnumSet.of(TargetType.SCRIPT), Action.CREATE, null, serviceRegistry);. This will still try to setup a database connection and fails on a nullpointer exception for metadata.

How can I create sql files from my Configuration in hibernate 5 without a database connection?

R C · Accepted Answer · 2022-07-27 08:17:59Z

4

Same issue here and could not find a way to prevent it from doing so, and as a workaround I have used hsqldb: read hibernate.properties + only modified driver/url/user/password to those of hsqldb, and only then handed the properties to hibernate to process them: this way hibernate gets a database to connect to (even though it does not need one for this task), while dialect remains intact, which is important for DDL/sql-scripts generation; tested and proved to work.

answered Jul 27, 2022 at 8:17

R C

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Comments

Konstantin Möllers · Accepted Answer · 2025-05-01 08:45:19Z

Building on R C's answer, I made the following approach work with Hibernate 5.6:

private ServiceRegistry buildServiceRegistry() {
    var properties = new Properties();
    properties.setProperty(AvailableSettings.DIALECT, MariaDBDialect.class);
    properties.setProperty(AvailableSettings.DRIVER, org.hsqldb.jdbcDriver.class.getName());
    properties.setProperty(AvailableSettings.URL, "jdbc:hsqldb:mem:test");
    properties.setProperty(AvailableSettings.USER, "sa");
    properties.setProperty(AvailableSettings.PASS, "");

    return new StandardServiceRegistryBuilder().applySettings(properties).build();
}

The rest works as described in the question:

ServiceRegistry serviceRegistry = buildServiceRegistry();
Metadata metadata = new MetadataSources(serviceRegistry).getMetadataBuilder().build();

SchemaExport schemaExport = new SchemaExport();
schemaExport.setHaltOnError(true);
schemaExport.setFormat(true);
schemaExport.setDelimiter(";");
schemaExport.setOutputFile("create.sql");
schemaExport.createOnly(EnumSet.of(TargetType.SCRIPT), metadata);

Make sure to include HSQLDB in your pom.xml if you're using Maven:

<dependency>
    <groupId>org.hsqldb</groupId>
    <artifactId>hsqldb</artifactId>
    <version>${hsqldb.version}</version>
</dependency>

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