i have a very simple class tutorial on the same topic. if you found this class quite turf to understand you can give a loot to my tutorial.

http://www.codingquery.com/php-mysql-connection-class-source-code

/**
*
* This function returns the field names of a table
*
*
* @param string $result the mysql resource pointer to a query
* @return returns a 2D array with the field names
*/
public function get_fields($result)
{
$row = $this->fetchAssoc($result);

if($row==TRUE)
return array_keys($row);
else
return false;
}
/**
* prevent sql injections
*
*/
public function prevent_injection($value) {
// Stripslashes
if (get_magic_quotes_gpc()) {
$value = stripslashes($value);
}
// Quote if not a number or a numeric string
if (!is_numeric($value)) {
$value = mysql_real_escape_string($value);
}
return $value;
}