Creating a Follow User mechanism - twitter-follow

Question

I am trying to create a follow mechanism, where in a user can follow the other. What I am doing is if A tries to follow B, I insert A email id against B in follow table. Now when A again tries to follow B, A id is checked against B, if found true, it redirects and shows already followed but if A tries to follow someone whom A hasnt, it adds them.
Now the problem is, the first part is working fine, but if I follow the same person again, it gets entered again in the table.
$temp=$_GET['temp'];
echo $temp;
mysql_connect('localhost','root','');
mysql_select_db('reviewed');
$query="SELECT follow_user from follow where my_email= '".$_SESSION['email']."'";
$data=mysql_query($query);
if (!$data) { // add this check.
die('Invalid query: ' . mysql_error()) ;
}
if(mysql_num_rows($data) > 0)
{
while($row=mysql_fetch_array($data))
{
$user=$row['follow_user'];
if($temp===$user)
{
header('Location:acq.php?success=1');
$_SESSION['message'] = 'Already Following.';
}
else
{
mysql_connect('localhost','root','');
mysql_select_db('reviewed');
$query="INSERT INTO follow (my_email, follow_user) VALUES('".$_SESSION['email']."','".$temp."')";
$data=mysql_query($query);
if (!$data) { // add this check.
die('Invalid query: ' . mysql_error()) ;
}
echo "Success";
}
}
}
else
{
mysql_connect('localhost','root','');
mysql_select_db('reviewed');
$query="INSERT INTO follow (my_email, follow_user) VALUES('".$_SESSION['email']."','".$temp."')";
$data=mysql_query($query);
if (!$data) { // add this check.
die('Invalid query: ' . mysql_error()) ;
}
echo "Success";
}

Answer 1

It looks to me as though you are adding a follow record for every user other than B that A is following. I think you might be able to fix this by restricting to B as well as A in your initial query i.e.
$query="SELECT follow_user from follow where my_email= '".$_SESSION['email']."' and follow_user = '".$temp"'";
You can then remove the while loop:
if(mysql_num_rows($data) > 0)
{
header('Location:acq.php?success=1');
$_SESSION['message'] = 'Already Following.';
}
else
{
mysql_connect('localhost','root','');
mysql_select_db('reviewed');
$query="INSERT INTO follow (my_email, follow_user) VALUES('".$_SESSION['email']."','".$temp."')";
$data=mysql_query($query);
if (!$data) { // add this check.
die('Invalid query: ' . mysql_error()) ;
}
echo "Success";
}