public function getSchemaTables()
    {
        if ($this->schemaTables !== null) {
            return $this->schemaTables;
        }
        $builder = $this->app['schema.builder'];

        /** @deprecated Deprecated since 3.0, to be removed in 4.0. */
        $builder['extensions']->addPrefix($this->app['schema.prefix']);

        $schema = new Schema();
        $tables = array_merge(
            $builder['base']->getSchemaTables($schema),
            $builder['content']->getSchemaTables($schema, $this->config),
            $builder['extensions']->getSchemaTables($schema)
        );
        $this->schema = $schema;

        return $this->schemaTables = $tables;
    }