$this
            ->addOption('mysql-engine', null, InputOption::VALUE_REQUIRED,  'MySQL engine (MyISAM, InnoDB, ...)')
            ->addOption('schema-dir', null, InputOption::VALUE_REQUIRED,  'The directory where the schema files are placed')
            ->addOption('output-dir', null, InputOption::VALUE_REQUIRED, 'The output directory')
            ->addOption('object-class', null, InputOption::VALUE_REQUIRED, 'The object class generator name')