PHP break, continue in 2 loop

Question

I'm a little confused about breaking out and continuing out of loops etc. I have 2 SQL queries that match user priveleges against the user's actual priveleges with the new ones put it. However, if some of the new priveleges match the one the user has, I want to skip the SQL insert and move on to the next one:

public static function insertPriveleges($user_id,$priveleges)
{
    $ex = explode(",",$priveleges); // separated by commas
    if(count($ex)>0)
    {
         $x = false;
         foreach($ex as $i => $priv)
         {
             $check_user = mysql_query("SELECT * FROM users_access_codes WHERE user_id='$user_id'") or die(mysql_error()); // get user's current priveleges
             while($check_data = mysql_fetch_array($check_user))
             {
                  if($check_data['access_code']!=$priv)
                  {
                      //if it doesn't match, insert 
                      $sql = "INSERT INTO users_access_codes (uaID,user_id,access_code) VALUES (NULL,'".$user_id."','$priv')";
                  }             
             }
         }
     }
}

I almost never have a situation that needs to match more than two things in loops. I need to make sure I don't end up with double priveleges for that user. I know there must be a 'continue' statement somewhere in the inner loop, but not sure where.

Answer 1

After your INSERT statement, you can add continue 2 to bring you back to the top of your foreach ($ex as .... You can also use break; in this case because there's nothing after your inner while.

However, you don't actually need it if you do it differently. Instead of reading the table for each privilege, just read all of them once and them compare.

This code will get all privileges from the database and then only inserts those that are missing, based on $ex; it uses array_diff() to calculate the difference between the two.

public static function insertPriveleges($user_id, $priveleges)
{
    $ex = explode(",", $priveleges); // separated by commas
    if (count($ex) > 0) {
         // get user's current priveleges
         $check_user = mysql_query("SELECT * FROM users_access_codes 
             WHERE user_id='$user_id'") or die(mysql_error()); 
         $actual = array();
         while ($row = mysql_fetch_array($check_user)) {
             $actual[] = $row['access_code'];
         }

         foreach (array_diff($ex, $actual) as $priv) {
             //if it doesn't match, insert 
             $sql = "INSERT INTO users_access_codes (uaID,user_id,access_code) VALUES (NULL,'".$user_id."','$priv')";
             mysql_query($sql);
         }
     }
}

Btw, you could consider using INSERT IGNORE INTO because of race conditions, but because you're not checking the statement return value, it won't matter here :)

Answer 2

Simply add a break after the INSERT:

public static function insertPriveleges($user_id,$priveleges)
{
    $ex = explode(",",$priveleges); // separated by commas
    if(count($ex)>0)
    {
         $x = false;
         foreach($ex as $i => $priv)
         {
             $check_user = mysql_query("SELECT * FROM users_access_codes WHERE user_id='$user_id'") or die(mysql_error()); // get user's current priveleges
             while($check_data = mysql_fetch_array($check_user))
             {
                  if($check_data['access_code']!=$priv)
                  {
                      //if it doesn't match, insert 
                      $sql = "INSERT INTO users_access_codes (uaID,user_id,access_code) VALUES (NULL,'".$user_id."','$priv')";
                      break;
                  }             
             }
         }
     }
}

To be complete I would recommand the reading of the following link: http://php.net/manual/en/faq.databases.php#faq.databases.mysql.deprecated