Need a quick help in PHP form validation...

Hi, this is my form wherein I can validate if the e-mail is valid or not, the phone number is less 7 or less, and if the form is complete. What I want now is, to validate of the Phone number already exists in my mysql database or not.

Here's my code:

<?php

$errors=0;
$error="<b>The following errors occured while processing your form input.</b><br /><br />";

$Name = $_POST['Name'];
$Email = $_POST['Email'];
$CellNumberPre = $_POST['CellNumberPre'];
$CellNumber = $_POST['CellNumber'];
$AlertOn = $_POST['AlertOn'];

if($Name=="" || $Email=="" || $CellNumberPre=="" || $CellNumber=="" || $AlertOn=="" ){
$errors=1;
$error.="<p>You did not enter one or more of the required fields. Please go <a href=\"javascript:history.go(-1)\"><b>back</b></a> and try again.</p>";
}

if(!preg_match("/^\d+$/",$CellNumber)){
$errors=1;
$error.="<p>Only numbers are accepted in the cell number field. Please go <a href=\"javascript:history.go(-1)\"><b>back</b></a> and try again.</p>";
}

if (strlen($CellNumber) < 7){
$errors=1;
$error.="<p>Your cellphone number is not valid. Please go <a href=\"javascript:history.go(-1)\"><b>back</b></a> and try again.</p>";
}


if(!eregi("^[a-z0-9]+([_\\.-][a-z0-9]+)*" ."@"."([a-z0-9]+([\.-][a-z0-9]+)*)+"."\\.[a-z]{2,}"."$",$Email)){
$error.="<p>Invalid email address entered. Please go <a href=\"javascript:history.go(-1)\"><b>back</b></a> and try again.</p>";
$errors=1;
}

if($errors==1) echo $error;
else{

$link = mysql_connect("localhost","username","password");
mysql_select_db("smsdatabase",$link);
$query="insert into sms_subscribers (name,email,cnp,cn,alerton) values ('".$Name."','".$Email."','".$CellNumberPre."','".$CellNumber."','".$AlertOn."')";
mysql_query($query);


?>

PHP:

Where will I insert the line of code wherein I'll validate of the $cellnumber already exists, and how can I do it?

Need help I'm just a php noob

That's all I hope someone can give me a simple to understand answer

 

$query='select 1 from sms_subscribers where cn='.mysql_real_escape_string($CEllNumber);
$result=mysql_query($query,$link);
if (mysql_num_rows($result)>0) 
{
//number exists;
}

PHP:

 

I guess that if you make the "cnp" column on your database setup UNIQUE; MySQL will not execute your query if you are trying to INSERT a value on "cnp" that already exists.

BTW; you really should read some articles about the mysql_real_escape_string() before you're site get hacked by a a SQL injection !!!

 

where will i insert this?

 

before

if($errors==1) echo $error;

PHP:

add

$query='select 1 from sms_subscribers where cn='.mysql_real_escape_string($CEllNumber);$result=mysql_query($query,$link);
if (mysql_num_rows($result)>0) 
{
    //number exists;
    $error.="<p>Cell phone number entered already exists. Please go <a href=\"javascript:history.go(-1)\"><b>back</b></a> and try again.</p>";
    $errors=1;
}

PHP:

you would also need to move

$link = mysql_connect("localhost","username","password");
mysql_select_db("smsdatabase",$link);

PHP:

above this added query, else it has nothing to connect to the DB with.

 

THANKS LFHOST! ur such a great help