Ci mysqli数据库连接

// 示例代码：数据库配置
$db['default'] = array(
    'dsn'    => '',
    'hostname' => 'localhost',
    'username' => 'your_username',
    'password' => 'your_password',
    'database' => 'your_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
);

// 示例代码：执行SQL查询
$query = $this->db->query('SELECT * FROM your_table');
if ($query) {
    $result = $query->result();
    foreach ($result as $row) {
        echo $row->column_name;
    }
} else {
    echo 'Query error: ' . $this->db->_error_message();
}

// 示例代码：设置连接超时时间
$db['default']['dbcollat'] = 'utf8_general_ci';
$db['default']['timeout'] = 10; // 设置连接超时时间为10秒