Send custom error message in Ajax error in codeigniter - php

Question

I am currently using Codeigniter and working on CRUD operation in one HTML form.
I am using Ajax for this create/read/update.
I have also used Transaction Management as best practices in a database query.
The Problem:
(1) I want separate Error message for Update and Insert Error. Which I did not get in the ajax error section.
(2) I have used the debugger to debug this problem but I do not get it proper.
Here is the Code of my controller.
Controller:
public function save_candidate_experience() {
$this->db->trans_start();
if(empty($postId))){
$query_staus = $this->test_model->insert_function( $data );
if($query_staus != TRUE) {
$msg = array('message'=>'Failed To Save! Erroe Wile Inserting.');
} else{
$msg = array('message'=>'Successfully Insert');
}
} else {
$query_staus2 = $this->test_model->update_function( $data );
if($query_staus2 != TRUE) {
$msg = array('message'=>'Failed To Save! Erroe Wile Updateing.');
}else{
$msg = array('message'=>'Successfully Updated');
}
}
if ($this->db->trans_status() === FALSE)
{
$this->db->trans_rollback();
echo json_encode ($msg);
}
else
{
$this->db->trans_commit();
echo json_encode ($msg);
}
}
This is the Model Code:
public function insert_function() {
$this->db->insert('table_name', $data);
if($this->db->affected_rows() > 0){
return TRUE;
} else{
return FALSE;
}
}
public function update_function() {
$this->db->where('id', $id);
$this->db->update('test_table', $data);
if($this->db->affected_rows() > 0){
return TRUE;
} else{
return FALSE;
}
}
Ajax Code in my view.
$.ajax({
type: 'POST',
async: true,
dataType: 'Json',
url: save_experience,
data: $('#candidata_exp_form').serialize(),
success: function (response) {
//doing something with ajax success
},error: function (msg)
{
alert(msg.message);
// I know I can give alert message here but.
//I don't want to give alert message here.
//I want to indicate user that the error occure whilt insert or update seperately.
}
});

Answer 1

You have to understand 2 things.
Form validation error and ajax error is different.
Ajax error - Is not validation error.
It means, suppose you call a function and there is php error in that function, or 404 error. At that time .error() will be called.
Ajax Success - No error(No syntax error).
So now you should write the logic in ajax success().
$.ajax({
type: 'POST',
async: true,
dataType: 'Json',
url: save_experience,
data: $('#candidata_exp_form').serialize(),
success: function (response) {
alert(response.message);// this will alert you the message which you have put in `json_encode()`
}
});