如果记录不在SQL中，请创建一个选项

Question

I have a combobox where I need to have on the options names of files in a folder that aren't register in a mySQL database.

The code is:

if ($handle = opendir('../media')) {
    $dbhost = 'HOST';
    $dbuser = 'USER';
    $dbpass = 'PASS';
    $conn = mysql_connect($dbhost, $dbuser, $dbpass);

    while (false !== ($entry = readdir($handle))) {

        if ($entry != "." && $entry != "..") {
            $sql = 'SELECT url FROM musics WHERE url="PREFIX_URL'.$entry.'"';
            mysql_select_db('DATABASE_NAME');
            $retval = mysql_query( $sql, $conn );
            if(! $retval )
   {
        echo "<option value='".$entry."'>";
        echo substr($entry,0,-4);   //This extracts the extension
        echo "</option><br />";
   }
   mysql_close($conn);
   }
   }

    closedir($handle);
}

Database have a column URL on table MUSICS where the content of it on each row is equal to the PREFIX_URL/nameOfTheFile.extension

My problem is that the combobox shows options with names of files that are registered on the database... And this is what I don't want to happen.

Can anybody help me?

Answer 1

To make this work, you could do the following.

use the php function mysql_num_rows ( resource $result )

So in your code,

   $retval = mysql_query( $sql, $conn );
   $numrows=mysql_num_rows($retval);  //new line inserted

Then in your if statement, change

if(! $retval )

to

if ($numrows==0)

What you are achieving is checking how many entries are for the current file. If there are 0 returned by mysql call, then display the select option. Your code before checked to see if mysql worked at all. However - mysql functions in PHP are deprecates, so you should use mysqli.