guide on validating this form please

[xcoderx]

ok i need help and tips on validating the fields. could someone show me how i go on about?

 

here is the form.php

<?php
$id 	= $_REQUEST['uid'];
$conn 	= db_connect();
$sql  	= "SELECT * FROM users WHERE id='".$id."'";
$result = mysql_query($sql, $conn) or die(mysql_error());  
$user_profile = mysql_fetch_array($result);
echo '<form action="update.php" method="post">';
echo '<font color="blue">Username:</font> <br/><input type="text" name="user_name" value="'.$user_profile['user_name'].'"> <br/><br/>';
echo '<font color="blue">First Name:</font> <br/><input type="text" name="f_name" value="'.$user_profile['f_name'].'"> <br/><br/>';
echo '<font color="blue">Last Name:</font> <br/><input type="text" name="l_name" value="'.$user_profile['l_name'].'"> <br/><br/>';
echo '<font color="blue">E-mail:</font><br/> <input type="text" name="email" value="'.$user_profile['email'].'"> <br/><br/>';
echo '<font color="blue">DOB:</font> <br/><input type="text" name="date" value="'.$user_profile['date'].'"> <br/><br/>';
echo '<input type="submit" name="submit" value="Update">';
echo '<input type="hidden" name="user_id" value="'.$user_profile['id'].'">';
echo '</form>';
?>
and here is the update.php which i must validate

<?php
session_start();
include 'db.inc.php';
//print_r($_POST);
$conn = db_connect();


$sql =" UPDATE users SET
                        user_name ='".$_POST['user_name']."',
                        f_name ='".$_POST['f_name']."',
                        l_name ='".$_POST['l_name']."',
                        email ='".$_POST['email']."',
                        date ='".$_POST['date']."'
                    WHERE id ='".$_POST['user_id']."' ";
mysql_query($sql,$conn);

header("Location:edit_a_user.php?uid=".$_POST['user_id']);
                    
//print $sql;
                        
?>

[xcasio]

This is how I would do it:

 

$sql = sprintf("UPDATE users SET user_name ='%s', f_name = '%s', l_name = '%s', email = '%s', date = '%s', WHERE id = %d ",
	mysql_real_escape_string($_POST['user_name']),
	mysql_real_escape_string($_POST['f_name']),
	mysql_real_escape_string($_POST['l_name']),
	mysql_real_escape_string($_POST['email']),
	mysql_real_escape_string($_POST['email']),
	mysql_real_escape_string($_POST['date']),
	$_POST['user_id']
	);

[xcoderx]

thats i know bro. but before updating i must check if any empty fields then data should not get updated. im not getting the idea how to.

[xcasio]

There's a lot of ways you could do that. If you're familiar with regex, you could just use that to verify the data. Otherwise, you could just use simple functions such as these:

 

strlen($string) to get the length of the string.

is_numeric(string) to check if the string is a number (for the id).

 

 

Also, to make the DOB field more consistent, I would do something like this:

if ($dob = strtotime($_POST['date'])) {
$dob = date('d/m/Y', $dob);
} else {
// Can't process the date.
}

[xcoderx]

well i just need to do it in a simpiliar  way something like this mebbe

 

if ($_POST['submit]==1) { 

    $errormsg = "";

    if ($_POST[user_name]){ 

        $user_name = $_POST[user_name];

else{ 

        $errormsg = "Please enter Username"; 

    } 

 

but im not getting the idea on how do i use to display error message on  the form.php if any field left empty and data not get updated till fields are filled

 

[Pikachu2000]

if( $_POST['submit'] == 1 ) isn't going to work for you, since there is no such value coming from that form. You have a hidden field in the form that will also need to be validated upon submission, so that could/should be used to see if the form has been submitted also. The if(isset($_POST['submit'])) method can be an issue with some browsers (especially Internet Exploder) that don't handle submit buttons properly.

[xcoderx]

whats the solution? could help me please?

[Pikachu2000]

Make sure the hidden user_id field is not empty when trim()'d and rtrim()'d, and at the same time validate it for the correct data type. Is the user_id field always expected to be an integer? If so, cast it as an integer type. Once that's handled, go on about validating the rest of the fields' values. Store any errors in an array so you can check for them, and echo them out later. The database insert should not be allowed to proceed unless the errors array is empty. If you need more help, or an example, just say so.

[xcoderx]

yes bro needed example.

[FURQAN]

The code for checking the null value is as follows 

<form method="post">
<input type="text" name="id">
<input type="submit" name="submit">
</form>

<?php
if(isset($_POST['submit'])) {
$v=$_POST['id'];
if(count($v)<=0) {
echo 'The field cannot be left blank';
}
else {
//whatever you want to do

}

}


?>


I think the above idea could help you with your problem

[xcoderx]

its not working.

[Pikachu2000]

What do you mean by not working?