php检查数据库中是否有电子邮件

Question

我正在尝试验证注册表中的电子邮件地址。我想检查该地址是否存在于数据库中。这是我第一次使用 php，但我不知道该怎么做。如果电子邮件包含错误字符，我会尝试添加我的代码和错误消息。

<?php


$dbhost = "localhost";
$dbusername = "test";
$dbpassword = "tester";
$database_name = "dbtest";


$link = mysql_connect("$dbhost", "$dbusername", "$dbpassword");
if(!$link){ die('Could not connect: ' . mysql_error());}

$db_selected = mysql_select_db("$database_name",$link);
if(!$db_selected){ die('Can\'t use foo: ' . mysql_error());}
            

        $email = strip_tags($_POST['email']);
        $verzija = strip_tags($_POST['mydropdown2']);
        $model = strip_tags($_POST['mydropdown']);
        
        $sql = mysql_query("INSERT INTO novice (naslov, podnaslov, vsebina, objavljeno)
                            VALUES ('$email', '$verzija', '$model', now())
                            ");

if(mysqli_query($link, $sql)){
    echo "Records added successfully.";
} else{
    echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}





// close connection

?>

<form action="insert.php" method="post">
        <label for="model">Phone model:</label>
        <select required aria-required="true" id="model" name="mydropdown">
            <option value="">Select...</option>
            <option value="x">x</option>
            <option value="xx">xx</option>
            
        </select>
        <label for="version">IOS version:</label>
        <select required aria-required="true" id="version" name="mydropdown2">
            <option value="">Select...</option>
            <option value="ax">ax</option>
            <option value="bx">bx</option>
            <option value="cx">cx</option>
        </select>
        <p>
            <br>
            <label for="emailAddress">Email Address:</label>
            <input type="text" id="emailAddress" placeholder="Your email..." name="email" required> </p>
        <input type="submit" value="Submit"> </form>

成功了。

Answer 1

现在您正在尝试插入而不是验证!

使用(使用 PDO):

$db = new PDO ("mysql:host=".$hostname.";dbname=".$dbname, $username, $password);

$query = $db -> prepare ("SELECT * FROM test WHERE email = :email");

$query -> execute (array (":email" => $email));

$count = $query -> rowCount();

if($count > "0")
{
 echo "email already exist";
}

你可以使用这个:

filter_var($email, FILTER_VALIDATE_EMAIL);

验证电子邮件格式。