检查数据库中是否已存在电子邮件 [英] Check if email already exists in database

问题描述

我有一个连接到数据库的测验表单，但是我需要防止插入重复的电子邮件条目。
我尝试了以下操作：

I have a quiz form that is connected to my database, however I need to prevent duplicate email entries being inserted. I have tried the following:

//Check for duplicate email addresses
            function checkEmail($email){
                $sql = DB::select('email')->from('myquiz')->where('email','=','$email')->execute(); 

                $result = mysql_result(mysql_query($sql),0) ;

                if( $result > 0 ){
                die( "There is already a user with that email!" ) ;
                }//end if
            }

但结束条目，这是我的所有代码（可能是我未在正确的位置运行它？）

But I 'm still getting duplicate entries, here is all my code (may be I'm not running this in the correct place?)

 public function action_myquiz() {
    $this->template->styles['assets/css/myquiz.css'] = 'screen';
    $this->template->jscripts[] = 'assets/scripts/myquiz.js';
    $this->template->content = View::factory('quiz/myquiz');
        $this->template->content->thanks = false;
        if ($this->request->post('entry')) {
            $post = $this->request->post('entry');

            //Check for duplicate email addresses
            function checkEmail($email){
                $sql = DB::select('email')->from('myquiz')->where('email','=','$email')->execute(); 

                $result = mysql_result(mysql_query($sql),0) ;

                if( $result > 0 ){
                die( "There is already a user with that email!" ) ;
                }//end if
            }

            // save participant's info
            $stmt = DB::query(Database::INSERT, 'INSERT INTO `myquiz` (`first_name`, `last_name`, `email`, `confirm_email`)
                                                                        VALUES (:first_name, :last_name, :email, :confirm_email)');                                                     
            $stmt->param(':first_name', $post['first_name']);
            $stmt->param(':last_name', $post['last_name']);
            $stmt->param(':email', $post['email']);
            $stmt->param(':confirm_email', $post['confirm_email']);
            try {
                $stmt->execute();
            //  var_dump($post);
            } catch (Exception $e) {
                FB::error($e);
            }

            $this->template->content->thanks = true;
        }
    }

推荐答案

两个问题：

1. 您永远不会调用 checkEmail（）函数，因此永远不会运行。您应该从函数中删除该代码，或者仅在需要运行该函数的地方调用该函数。


2. 在该函数中，您正在检查是否存在不等于 $ email的电子邮件。 PHP仅会解析双引号中的变量-更改该行以使用 where（'email'，'='， $ email）代替。

1. You're never calling your checkEmail() function so it's never running. You should either remove that code from the function or just call the function where it needs to run.
2. In that function you're checking that no email exists that literally equals "$email". PHP will only parse variables in double quotes - change that line to use where('email','=',"$email") instead.

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