PHP is inserting two duplicate rows in MYSQL database

Question

I am having trouble with PHP and MYSQL. I have an HTML form which when submitted runs the following PHP script.The problem is that the following PHP code is inserting the data into the database twice. I think it is something to do with the following PHP and not the database:

<?php

$first_name = $_POST['firstname'];
$last_name = $_POST['lastname'];
$display_name = $_POST['displayname'];
$email = $_POST['email'];
$password = $_POST['password'];
$add_line1 = $_POST['addline1'];
$add_line2 = $_POST['addline2'];
$city = $_POST['city'];
$county = $_POST['county'];
$postcode = $_POST['postcode'];

$sql = "INSERT INTO members (memberID, 
memberPassword, 
memberFirstName, 
memberLastName,
memberAddressLine1, 
memberAddressLine2, 
memberCity,
memberCounty, 
memberPostcode, 
memberDisplayName) 
VALUES ('$email', 
'$password', '$first_name', '$last_name',
 '$add_line1', '$add_line2','$city',
 '$county', '$postcode', '$display_name')";

if (!mysqli_query($conn,$sql))
{
     die('Error: ' . mysqli_error($conn));
}
mysqli_query($conn,$sql);
echo 'Guest Added';
mysqli_close($conn);

?>

Tushar · Accepted Answer · 2013-03-18 22:28:29Z

7

if (!mysqli_query($conn,$sql))
{
     die('Error: ' . mysqli_error($conn));
}
mysqli_query($conn,$sql);

You have mysqli_query($conn,$sql); in your code twice. Once in the if(), and once outside. Each of these will insert into your database.

The point to note here is that the mysqli_query inside the if is evaluated - that is, it is run and the if statement executes on the result of the function call. Thus, you do not need to call it again.

answered Mar 18, 2013 at 22:28

Tushar

8,05934 silver badges39 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user1467267 Over a year ago

Yes; mysqli_query($conn,$sql); can be removed and just add else{} to the if-statement and there echo the 'Guest Added' message', as an indicator of success.

underflow Over a year ago

Thanks for you help - didn't realise it ran when being evaluated.

Volkan · Accepted Answer · 2013-03-18 22:38:09Z

1

Tushar pointed out the twin mysqli queries and he is right, besides that, the code as is now will cause you security troubles since it allows sql injection...

Please modify your code as follows:

 $first_name   = mysqli_escape_string($conn, $_POST['firstname']);
 $last_name    = mysqli_escape_string($conn, $_POST['lastname']);
 $display_name = mysqli_escape_string($conn, $_POST['displayname']);
 $email        = mysqli_escape_string($conn, $_POST['email']);
 $password     = mysqli_escape_string($conn, $_POST['password']);
 $add_line1    = mysqli_escape_string($conn, $_POST['addline1']);
 $add_line2    = mysqli_escape_string($conn, $_POST['addline2']);
 $city         = mysqli_escape_string($conn, $_POST['city']);
 $county       = mysqli_escape_string($conn, $_POST['county']);
 $postcode     = mysqli_escape_string($conn, $_POST['postcode']);

answered Mar 18, 2013 at 22:38

Volkan

2,2101 gold badge15 silver badges14 bronze badges

1 Comment

underflow Over a year ago

Great advice - new to PHP and good to know practices regarding security.

Collectives™ on Stack Overflow

PHP is inserting two duplicate rows in MYSQL database

2 Answers 2

2 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related