stop inserting data in the database when refreshing the page

问题

I am looking for a way to stop inserting or sending data in the database when refreshing the page.

here is my code:

user_details_page.php

<form action="confirm_page.php" method="post" >
User Name:  
<input  type="text" name="username" >
User Email
<input  type="text" name="useremail" >
Password:  
<input  type="text" name="password" >
<input type="submit"  name="submit" >
</form>

confirm_page.php

if (isset($_POST['submit'])) 
{
$user= $_POST['username'];
$email = $_POST['useremail'];
$pass= $_POST['password']; 

mysql_query("INSERT INTO table (username, useremail, email) VALUES ('$username','$useremail','$email');

}

so the problem everytime I refresh the confirm page.php the data is sent to the database. how to stop this?

回答1:

Header the user to a new page :

if (isset($_POST['submit'])) 
{
  $user= $_POST['username'];
  $email = $_POST['useremail'];
  $pass= $_POST['password']; 

  mysql_query("INSERT INTO table (username, useremail, email) VALUES(`$username','$useremail','$email')");

}
//best outside the if statement so user isn't stuck on a white blank page.
header("location: landing_page.php");
exit;

By doing this the user who refreshes will be refreshing landing_page.php which means it won't do the insert twice.

best advice: do a check to see if user exists first if so don't insert!

回答2:

What is going on here is that when you refresh page, the form is submitted twice.

To prevent this, you can use sessions:

session_start();

if( $_SESSION['submit'] == $_POST['submit'] && 
     isset($_SESSION['submit'])){
    // user double submitted 
}
else {
    // user submitted once
    $_SESSION['submit'] = $_POST['submit'];        
}

回答3:

Once an insert or update is done in your code you always need to redirect to another page.

See here on how to do that: How to make a redirect in PHP?

(You want to use a PHP redirect, not a Javascript or HTML one, because you obviously really need this to work.)

The confirm page should be what you redirect to after the update, not what does the insert.

回答4:

confirm_page.php:

if (isset($_POST['submit'])) 
{
$user= $_POST['username'];
$email = $_POST['useremail'];
$pass= $_POST['password']; 

mysql_query("INSERT INTO table (username, useremail, email) VALUES ('$username','$useremail','$email')"); // <-- missing endquote and bracket here

header('Location: somewhere_else.php');
exit;
}

回答5:

The best way to prevent that is to add header('Location: filename') after your query. Thus in your case,

if (isset($_POST['submit'])) 
{
$user= $_POST['username'];
$email = $_POST['useremail'];
$pass= $_POST['password']; 

mysql_query("INSERT INTO table (username, useremail, email) VALUES ('$username','$useremail','$email');
//must be inside the condition to prevent too many redirects
header('Location: user_details_page.php');
}

回答6:

i have this solution by using session

<?php session_start();
        if(isset($_POST[$_SESSION[a][count($_SESSION[a])-1]])){
            echo "somthing....";
            unset($_SESSION[a]);
        }
        else{     
                        echo '<form method="post">';
                              $_SESSION["a"]=array();
                              $_SESSION["a"][0]="a".rand(1,100);
                        echo '<input name="'.$_SESSION["a"][0].'"><br>';
                              $_SESSION["a"][1]="a".rand(1,100);
                        echo '<input name="'.$_SESSION["a"][1].'"><br>';
                              $_SESSION["a"][2]="a".rand(1,100);
                        echo '<input name="'.$_SESSION["a"][2].'"><br>';
                              $_SESSION["a"][3]="a".rand(1,100);
                        echo '<input type="submit" name="'.$_SESSION["a"][3].'" value="submit"><br>';
                        echo '</form>';
        }               
?>

回答7:

We can stop it without redirect , best way to use PHP $_SESSION like this :

if($_SERVER['REQUEST_METHOD'] == 'POST' && empty($_SESSION['form_submit']) )
{ 
    extract($_POST);
    $sql=""INSERT INTO table (username, useremail, email) VALUES('$username','$useremail','$email')";
    $_SESSION['form_submit']='true'; 
} 
else
 {
    $_SESSION['form_submit']='NULL';
 }

回答8:

The fast way is to redirect the page to it's current location:

if (isset($_POST['submit'])) 
{
//do somthing
header("Location: $current_url");
}

回答9:

I was facing the same problem. Was trying to add some data and everytime when I refreshed the page it gets added again. It happens because the page is not loading. For that you need to add:

<?php ob_start();?> in your header file, then include the header in the current file you are working on. After that use the below code

    if (isset($_POST['submit'])) 
{
  $user= $_POST['username'];
  $email = $_POST['useremail'];
  $pass= $_POST['password']; 

  mysql_query("INSERT INTO table (username, useremail, email) VALUES(`$username','$useremail','$email')");

//user it before if statement
header("location: onthesamepage/oranyotherpage.php");
}

回答10:

if($_POST(submit)
{
 //database insertion query
 // if successful insertion
    {
echo"<script language='javascript'>alert('successfully inserted')</script>";
echo"<script>document.location='your_page.php';</script>;
    }
}

来源：https://stackoverflow.com/questions/18115665/stop-inserting-data-in-the-database-when-refreshing-the-page

标签

php

mysql

database

load

refresh