很多'if语句'，还是冗余的mysql查询？

Question

$url = mysql_real_escape_string($_POST['url']); $shoutcast_url = mysql_real_escape_string($_POST['shoutcast_url']); $site_name = mysql_real_escape_string($_POST['site_name']); $site_subtitle = mysql_real_escape_string($_POST['site_subtitle']); $email_suffix = mysql_real_escape_string($_POST['email_suffix']); $logo_name = mysql_real_escape_string($_POST['logo_name']); $twitter_username = mysql_real_escape_string($_POST['twitter_username']);

with all those options in a form, they are pre-filled in (by the database), however users can choose to change them, which updates the original database. Would it be better for me to update all the columns despite the chance that some of the rows have not been updated, or just do an if ($original_db_entry = $possible_new_entry) on each (which would be a query in itself)?

Thanks

Answer 1

I'd say it doesn't really matter either way - the size of the query you send to the server is hardly relevant here, and there is no "last updated" information for columns that would be updated unjustly, so...

By the way, what I like to do when working with such loads of data is create a temporary array.

$fields = array("url", "shoutcast_url", "site_name", "site_subtitle" , ....); 

foreach ($fields as $field)
 $$field = mysql_real_escape_string($_POST[$field]);

the only thing to be aware of here is that you have to be careful not to put variable names into $fields that would overwrite existing variables.

Update: Col. Shrapnel makes the correct and valid point that using variable variables is not a good practice. While I think it is perfectly acceptable to use variable variables within the scope of a function, it is indeed better not use them at all. The better way to sanitize all incoming fields and have them in a usable form would be:

$sanitized_data = array();
$fields = array("url", "shoutcast_url", "site_name", "site_subtitle" , ....); 

foreach ($fields as $field)
 $sanizited_data[$field] = mysql_real_escape_string($_POST[$field]);

this will leave you with an array you can work with:

$sanitized_data["url"] = ....
$sanitized_data["shoutcast_url"] = ....