使用MySQLI处理SELECT查询的结果时出现问题

Question

我尝试使用的基本控制结构是用用户名和电子邮件查询数据库，这两个都是唯一的键，如果其中任何一个在数据库中，请让用户知道它们被拿走了，并请选择其他东西。我遇到的问题是以可用的形式获取结果数据，然后我可以对照它检查用户提供的数据。

我删掉了准备好的插入语句，以及验证例程，因为它们都运行良好。

DB connection snippit

try {
    if(!($dbc = new mysqli(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME))){      // Creates the $dbc variable object so we can
                                                                           // have a connection to the database.
                                                                           // uses mysqli functions.
    throw new Exception;
    }
}
catch (Exception $e) {
    echo '<p>Could not connect to the database. Please contact the system administrator.</p>';
} 

注册脚本的代码段

//before this was validation routines, if anything was wrong the script generated something into $reg_errors which is an array.
if(empty($reg_errors))
{
//queries database if there are any matches for username or email from user input.
if($stmt = $dbc->prepare("SELECT `email`, `username` FROM `users` WHERE `email` = ? OR `username` = ?"))
{
    $stmt->bind_param("ss", $e, $u);
    $stmt->execute();
    $stmt->store_result();
    $rows = $stmt->num_rows;                   //gives the number of rows returned from SELECT query. 0 means no dupes, 1 means one record has BOTH email and username, 2 means two different records (one with email, one with username)
 ##THIS IS WHERE I'M RUNNING INTO TROUBLE GETTING THE DATA IN A USABLE FORM##
    $stmt->close();
} else {
    echo "<p>Can't talk to database right now. Try again later, please.</p>";
}
        if($rows==0)            //no dupes of username or email, so let's try and add them into the DB
        {
            //prepared statement for insertion into DB
            //also get's the count of affected rows. 1 means record inserted correctly. 
        //asks DB if a new row was created, and if so, thanks user for 
        //registration on the site & sends an email to their email.
        //if query doesnt work, an error is triggered
        if($count==1) {
            //constructs a thank you note and emails it to the user, using the email they supplied.
            exit(); 
            } else {
                echo "<p>Unable to process your registration at this time. Please try again later..</p>";
            }
    } else {                    // both username and email might be already used in DB, and error msgs are generated for array.
        if($rows==2) {          // this checks to make sure both entries are dupes        
            $reg_errors['email'] = 'This email address has already been registered. If you have forgotten your password, use the link to the right to have your password sent to you.';
            $reg_errors['username'] = 'This username has already been registered. Please try another.';
        } else {                //this checks to see which of the two (email or username) is already in DB if both arent dupes.
            if((__NEED SOMETHING HERE FROM DB QUERY___ == $_POST['email']) && (__NEED SOMETHING HERE FROM DB QUERY___ == $_POST['username'])) {   //both match entries in DB
                $reg_errors['email'] = 'This email address has already been registered. If you have forgotten your password, use the link to the right to have your password sent to you.';
                $reg_errors['username'] = 'This username has already been registered with this email address. If you have forgotten your password, use the link to the right to have your password sent to you.';
            } elseif(__NEED SOMETHING HERE FROM DB QUERY___==$_POST['email']) {        // email match
                    $reg_errors['email'] = 'This email address has already been registered. If you have forgotten your password, use the link to the right to have your password sent to you.';
            } elseif(__NEED SOMETHING HERE FROM DB QUERY___==$_POST['username']) {     // username match
                $reg_errors['username'] = 'This username has already been registered. Please try another one.';
            }
        }       // end of $rows==2 ELSE
    }           // end of $rows == 0 IF
    } else {           // end of empty reg_errors conditional
        //do something if the reg_error array isnt empty..
    }  

我很确定答案在于迭代和使用结果mysqli对象中的meta_data，但在几天的时间里，我的头撞在墙上，像个疯子一样翻阅mysqli-php手册页面后，我仍然没有弄清楚我应该做什么。有人能给我指正确的方向吗？

Answer 1

从注册脚本开始，您尝试过这个吗：

if($stmt = $dbc->prepare("SELECT `email`, `username` FROM `users` WHERE `email` = ? OR `username` = ?"))
{
    $stmt->bind_param("ss", $e, $u);
    $stmt->execute();
    $stmt->bind_result($email, $username);
    $rows = $stmt->num_rows;
    //Move Conditionals Up a Little
    if( $rows == 0 ) {    //If No Records are Found
        //Continue Registration
    }
    else if( $rows == 1 ) { //If One Record is Found
        $stmt->fetch();
        //Do Something With $email and $username from DB Here
    }
    else { //If More than One Record is Found
        while( $stmt->fetch() ) {  //Iterate Through Records
            //Do Something With $email and $username from DB Here
        }
    }
}