PHP：运行此代码时检查电子邮件是否已存在

时间：2011-02-18 16:44:43

标签： php

我构建了一个非常简单的PHP表单，允许用户使用以下PHP代码发送应用程序：

if($_SERVER['REQUEST_METHOD'] == 'POST')
    {
        $host = '###';
        $username = '###';
        $pass = '###';

        mysql_connect($host,$username,$pass);
        mysql_select_db("###");

        $status    = mysql_real_escape_string($_POST['status']);
        $firstname = mysql_real_escape_string($_POST['firstname']);
        $lastname  = mysql_real_escape_string($_POST['lastname']);
        $email     = mysql_real_escape_string($_POST['email']);
        $url       = mysql_real_escape_string($_POST['url']);

        $query = "INSERT INTO creathive_applications 
                  VALUES (NULL,'$status','$firstname','$lastname','$email','$url')";

        $result = mysql_query($query) or trigger_error(mysql_error().". Query: ".$query);
    }

我想要做的是确保同一个人不应用TWICE，所以如果电子邮件地址已经存在于数据库中，那么它将在表单上显示一条消息“抱歉看起来你已经应用了”

这是HTML表单，我已在字段集中添加了消息，因此需要执行a）如果电子邮件退出或显示成功消息，则显示此消息然后b）将#membership表单添加到URL以使视图跳转到页面上的表单，以便用户将看到消息。对此可以有任何帮助吗？致谢

    <form action="" method="post">
                            <fieldset id="membershipform">
                    <div id="error"><p>sorry email in use</p></div>
<div id="success"><p>Thanks your application has been sent</p></div>
                                <ul class="clearfix">
                                    <li id="li-status">
                                        <span>I am a:</span>
                                        <menu>
                                            <li><label for="student"><input type="radio" name="status" id="student" checked="checked" value="Graduate" /> Graduate</label></li>
                                            <li><label for="student2"><input type="radio" name="status" id="student2" value="Undergraduate" /> Undergraduate</label></li>
                                        </menu>
                                    </li>
                                    <li id="li-firstname">
                                        <label for="firstname">First Name</label> <input name="firstname" type="text" placeholder="First Name" id="firstname" title="First Name" />
                                    </li>
                                    <li id="li-lastname">
                                        <label for="lastname">Last Name</label> <input name="lastname" type="text" placeholder="Last Name" id="lastname" title="Last Name" />
                                    </li>
                                    <li id="li-email">
                                        <label for="email">Email address</label> <input name="email" type="text" placeholder="Email address" id="email" title="Email address" />
                                    </li>
                                    <li id="li-url">
                                        <label for="url">URL</label> <input name="url" type="text" placeholder="URL of something you've made" id="url" title="URL of something you've made" />
                                    </li>
                                    <li id="li-buttons">
                                        <input name="submit" type="submit" value="Send Application &#9658;" title="Send Application" />
                                    </li>
                                </ui>
                            </fieldset>
                        </form>

5 个答案:

答案 0 :(得分：0)

在插入之前执行选择查询以验证电子邮件没有任何条目：

select from creathive_applications where email = $email

如果有任何结果返回，则显示您的消息而不是插入记录。如果电子邮件已经存在，您可以添加javascript onload代码以将表单移动到#membershipform。

答案 1 :(得分：0)

  1. 您可以更改表格，以便电子邮件ID是主要的，因此它将是唯一的。

  2. 您可以查看其他查询

    从creathive_applications中选择emai ='$ email'

答案 2 :(得分：0)

很简单，您必须根据数据库进行检查。

if($_SERVER['REQUEST_METHOD'] == 'POST'){
    $host = '###';
    $username = '###';
    $pass = '###';

    mysql_connect($host,$username,$pass);
    mysql_select_db("###");

    $status    = mysql_real_escape_string($_POST['status']);
    $firstname = mysql_real_escape_string($_POST['firstname']);
    $lastname  = mysql_real_escape_string($_POST['lastname']);
    $email     = mysql_real_escape_string($_POST['email']);
    $url       = mysql_real_escape_string($_POST['url']);

    $query_check = "SELECT COUNT(*) as existents FROM creathive_applications .... emailfiel = 'email_entered'";
    switch($query_check['existents']){
        case 0:
            //do the insert operation
            $query = "INSERT INTO creathive_applications VALUES (NULL,'$status','$firstname','$lastname','$email','$url')";
            $result = mysql_query($query) or trigger_error(mysql_error().". Query: ".$query);
        break;
            default:
            echo "no no";
    }
}

答案 3 :(得分：0)

检查数据库中是否存在$email，以及是否设置了$error = 1。然后，如果$error = 1，则打印消息。

$emailchk  = mysql_query("SELECT * FROM creathive_applications WHERE email = '$email'");
if(mysql_num_rows($emailchk) > 0) {  
    $error = 1;  
}

if isset($error) {  
    echo '<div id="error"><p>sorry email in use</p></div>';  
}

答案 4 :(得分：0)

你可以这样做：

PHP代码： 

if($_SERVER['REQUEST_METHOD'] == 'POST')
{
    $host = '###';
    $username = '###';
    $pass = '###';
    $emailerror = null;

    mysql_connect($host,$username,$pass);
    mysql_select_db("###");

    $status    = mysql_real_escape_string($_POST['status']);
    $firstname = mysql_real_escape_string($_POST['firstname']);
    $lastname  = mysql_real_escape_string($_POST['lastname']);
    $email     = mysql_real_escape_string($_POST['email']);
    $url       = mysql_real_escape_string($_POST['url']);

    $emailchk  = mysql_query("SELECT * FROM creathive_applications WHERE email = '$email'");
    if(mysql_num_rows($emailchk) == 0) {  
        $query = "INSERT INTO creathive_applications VALUES (NULL,'$status','$firstname','$lastname','$email','$url')";
        $result = mysql_query($query) or trigger_error(mysql_error().". Query: ".$query);
    }else{
        $emailerror = '<span style="color:rgb(255,0,0)">Email already taken</span>';
    }
}

HTML （必须在同一个文件中）： 

<form action="" method="post">
                            <fieldset id="membershipform">
                    <div id="error"><p>sorry email in use</p></div>
<div id="success"><p>Thanks your application has been sent</p></div>
                                <ul class="clearfix">
                                    <li id="li-status">
                                        <span>I am a:</span>
                                        <menu>
                                            <li><label for="student"><input type="radio" name="status" id="student" checked="checked" value="Graduate" /> Graduate</label></li>
                                            <li><label for="student2"><input type="radio" name="status" id="student2" value="Undergraduate" /> Undergraduate</label></li>
                                        </menu>
                                    </li>
                                    <li id="li-firstname">
                                        <label for="firstname">First Name</label> <input name="firstname" type="text" placeholder="First Name" id="firstname" title="First Name" />
                                    </li>
                                    <li id="li-lastname">
                                        <label for="lastname">Last Name</label> <input name="lastname" type="text" placeholder="Last Name" id="lastname" title="Last Name" />
                                    </li>
                                    <li id="li-email">
                                        <label for="email">Email address</label> <input name="email" type="text" placeholder="Email address" id="email" title="Email address" /> <?php echo $emailerror;?>
                                    </li>
                                    <li id="li-url">
                                        <label for="url">URL</label> <input name="url" type="text" placeholder="URL of something you've made" id="url" title="URL of something you've made" />
                                    </li>
                                    <li id="li-buttons">
                                        <input name="submit" type="submit" value="Send Application &#9658;" title="Send Application" />
                                    </li>
                                </ui>
                            </fieldset>
                        </form>
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