/**
* Simple Query
* This is a simplified version of the query() function. Internally
* we only use it when running transaction commands since they do
* not require all the features of the main query() function.
*
* @access public
* @param string the sql query
* @return mixed
*/
function simple_query($sql)
{
$proxy_setting = load_db_proxy_setting($this->group_name, $this->is_write_type($sql), $this->db_force_master);
if (is_array($proxy_setting) && !empty($proxy_setting)) {
$proxy_setting_key = key($proxy_setting);
$this->group_name = $proxy_setting_key;
foreach ($proxy_setting[$proxy_setting_key] as $key => $val) {
$this->{$key} = $val;
}
$proxy_conn_id = 'conn_' . $proxy_setting_key;
$CI =& get_instance();
if (isset($CI->{$proxy_conn_id}) && is_resource($CI->{$proxy_conn_id})) {
$this->conn_id = $CI->{$proxy_conn_id};
//$this->reconnect();
} else {
//$this->_close($this->conn_id);
$this->conn_id = false;
$this->initialize();
$CI->{$proxy_conn_id} = $this->conn_id;
}
$this->reset_force_master();
}
if (!$this->conn_id) {
$this->initialize();
}
if (defined('SQL_LOG_WRITE') && SQL_LOG_WRITE === true) {
$CI =& get_instance();
$CI->load->library('log');
$CI->log->write("ip={$CI->input->ip_address()}; host={$this->hostname}; dbname={$this->database}; group={$this->group_name};\r\n" . preg_replace("/\\s+/", " ", $sql), 'sqllog/log');
}
return $this->_execute($sql);
}
/**
* Simple Query
* This is a simplified version of the query() function. Internally
* we only use it when running transaction commands since they do
* not require all the features of the main query() function.
*
* @param string the sql query
* @return mixed
*/
public function simple_query($sql)
{
//load_db_proxy_setting方法这里写在helper中，也可以直接写在该类中，写在helper中则需要在自动加载中加载该helper
//该方法的作用是根据当前链接group name 和sql读写类型，以及是否强制使用主库判断使用哪个链接。使用主库 OR 重库？
//主重库的负载均衡，单点故障都可以在这里考虑。也就是根据3个参数返回一个可用的配置数组。
$proxy_setting = load_db_proxy_setting($this->group_name, $this->is_write_type($sql), $this->db_force_master);
if (is_array($proxy_setting) && !empty($proxy_setting)) {
$proxy_setting_key = key($proxy_setting);
$this->group_name = $proxy_setting_key;
//将当前配置重新赋值给类的属性，如果database.php配置的是DSN字符串，则需要在load_db_proxy_setting中做处理
foreach ($proxy_setting[$proxy_setting_key] as $key => $val) {
$this->{$key} = $val;
}
//定义链接ID为conn_前缀
$proxy_conn_id = 'conn_' . $proxy_setting_key;
$CI =& get_instance();
//赋值给CI超级对象或者直接从CI超级对象中读取
if (isset($CI->{$proxy_conn_id}) && is_resource($CI->{$proxy_conn_id})) {
$this->conn_id = $CI->{$proxy_conn_id};
} else {
$this->conn_id = false;
$this->initialize();
$CI->{$proxy_conn_id} = $this->conn_id;
}
//强制只一次有效，下次查询失效，防止一直强制主库
$this->reset_force_master();
}
if (!$this->conn_id) {
$this->initialize();
}
return $this->_execute($sql);
}
