How to output error for double entry PHP MVC - php

Question

I am using Codeigniter and I have created a code that checks if there is the same entry already in the database. but i dont know how i will output the error message. the boolean is not working.
VIEW
<h8><b>Add New Service: For single upload. <?php echo $status; ?></b></h8><hr>
<form action="<?php echo base_url(); ?>some_controller/insertServ" method="post">
<center>Service Name: <input type="text" name="ci_name"/>
<input type="submit" class="classname" value="Save"/></center>
</form>
CONTROLLER
public function insertServ(){
/* logic behind adding a new service
*/
$ci_name = $this->input->post('ci_name');
$success = $this->some_model->addCI($ci_name);
if($success == TRUE)
$this->viewMap_add(TRUE);
else $this->viewMap_add(FALSE);
}
public function viewMap_add($success = NULL){
/* Shows the list of the services with a dialog box for
* adding a new service
*/
if($success == NULL)
$status = 'N/A';
else if($success == TRUE)
$status = 'Success';
else $status = 'FAILED';
$data['status'] = $status;
$data['current_user']=$this->session->userdata('email');
$data['mapList'] = $this->some_model->getMapped();
$this->load->view('templates/header.php',$data);
$this->load->view('some_page/servList_add.php',$data);
}
MODEL
public function addCI($ci_name){
/* Adds a new service
*/
$ci_name = $this->db->escape_str($ci_name);
$queryStr = "Select service from appwarehouse.service where service = '$ci_name'";
$query = $this->db->query($queryStr);
if($query->num_rows()>0){
echo "result already exists";
}
else{
$queryStr = "INSERT INTO appwarehouse.service(service) VALUES ('$ci_name');";
$query = $this->db->query($queryStr);}
}

Answer 1

First off, your model method addCI isn't returning anything. Fix that.
Then, you can avoid all the mess by simply removing one layer of code and sending the status value directly:
public function insertServ:
if($success)
$this->viewMap_add('Success');
else
$this->viewMap_add('FAILED');
And then just remove all the if-elses in the viewMap_add method.
Also, since you didn't tell exactly what is the problem, try doing the var_dump on the status variable in insertServ or just:
var_dump($this->some_model->addCI($ci_name));
UPDATE
Here is how your model method should look like (nothing to echo there, but return a boolean):
public function addCI($ci_name){
/* Adds a new service
*/
$ci_name = $this->db->escape_str($ci_name);
$queryStr = "Select service from appwarehouse.service where service = '$ci_name'";
$query = $this->db->query($queryStr);
if($query->num_rows()>0){
return false; // <---- this one is important
}
else{
$queryStr = "INSERT INTO appwarehouse.service(service) VALUES ('$ci_name');";
$query = $this->db->query($queryStr);
return true; // <---- and this one
}
}