如何使用codeigniter从本地数据库同步到服务器数据库

$db['default'] = array(
    'dsn'    => '',
    'hostname' => 'localhost',
    'username' => 'local_username',
    'password' => 'local_password',
    'database' => 'local_database',
    'dbdriver' => 'mysqli',
    'dbprefix' => '',
    'pconnect' => FALSE,
    'db_debug' => (ENVIRONMENT !== 'production'),
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt' => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE
);

$db['remote'] = array(
    'dsn'    => '',
    'hostname' => 'remote_server_ip',
    'username' => 'remote_username',
    'password' => 'remote_password',
    'database' => 'remote_database',
    'dbdriver' => 'mysqli',
    'dbprefix' => '',
    'pconnect' => FALSE,
    'db_debug' => (ENVIRONMENT !== 'production'),
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt' => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE
);

class Sync extends CI_Controller {

    public function __construct() {
        parent::__construct();
        $this->load->database('default', TRUE);
        $this->load->database('remote', TRUE);
    }

    public function index() {
        // 获取本地数据库的所有表
        $tables = $this->db->list_tables();

        foreach ($tables as $table) {
            // 获取本地表的数据
            $query = $this->db->get($table);
            $data = $query->result_array();

            // 插入数据到远程数据库
            $this->db->insert_batch($table, $data);
        }

        echo "同步完成！";
    }
}