how to make "follow" button change to "following" social network codeigniter - codeigniter

Question

I am making a social network using Codeigniter and I'm trying to make the users view show a button when you are already following a person how do I do that??
Model
<?php
class User_model extends CI_Model {
function get_All(){
$this->db->select('*');
$this->db->from('membership');
// $this->db->join('following', 'following.id = membership.id');
$q = $this->db->get();
if($q->num_rows() > 0) {
foreach ($q->result() as $rows) {
$data[] = $rows;
}
return $data;
}
}

Answer 1

It's a little bit of work. Assuming that all users can be searched, you might have a list of all users, and of the 'friends' of all users. Then you run through the two comparing them. The following is an idea:
Database Members: All members |ID_User|...other user stuff...
Database Followers: Lists all friendship |ID_User|ID_Follower|
You need two queries for this: One for all, and one for Followers where ID_User=$UserID. As you run through all members as you suggest, then you can
function get_Followers(){
$friends= $this->db->query('SELECT * FROM Followers WHERE ID_User=$UserID');
$follow_array=$row->ID_Follower;
}
Now:
$follow_array //A list of all friends.
$q //Your original list of members
Then you can use:
if($q->num_rows() > 0) {
foreach ($q->result() as $rows) {
if(in_array($rows->ID_Follower, $Follower_array))
{
$data=true;
}
else
{
$data=false;
}
}
return $data;
}
Beware however, this may be a very server-heavy operation.

Answer 2

I'm going to assume you're talking about visiting a persons profile and if you are following that person you see a button. That only requires one query and logic in the view itself.
Going on this assumption you're already passing the person who's profile you're viewing to the view so all you need is a list of people the viewer is following to compare that id to.
I'm not really sure what your query in your code is doing since there's no description of your database so I'll give the code the way the tables should be laid out, which is a user table and a following table that is just a join table on the users. Assuming the following table has 3 columns id, userId, followingId where userId is you and followingId is the person you are following.
Controller
$data['following'] = $this->modelName->getFollowing($userId); //pass current userId
$this->load->view('viewName',$data);
Model:
public function getFollowing($userId)//$userId to be passed as the person viewing.
{
$this->db->where('userId',$userId);
$data = $this->db->get('following');
if($this->db->num_rows() > 0)
{
return $data;
} else {
$data=array();
$return $data;
}
Then in the view it's a simple if statement.
if(in_array($profileId,$following))
{
echo button;
}