Problem in duplication after clicking submit button multiple times - php

Question

My main problem is with that code in which when I click on submit buttons many times, it inserts duplication many times in the database in which I need to avoid that. Please help me to solve this problem. These are the two tables in which I am trying to insert. mat_ans_options_choose and mat_answer.
$val = $this->input->post(null, true);
$val['id'] = $this->input->post('id');
$val['sub_type'] = $this->input->post('sub_type');
$val['timeout'] = $this->input->post('timeout');
$val['level'] = $this->input->post('level');
$val['mat_category'] = $this->input->post('mat_category');
$option = $val['option'] = $this->input->post('option');
$type = $this->input->post('type');
$marks = [];
$uid = $this->session->userdata('id');
if (isset($val['id']) && isset($option)) {
$query = $this->db->query("SELECT * FROM mat_ans_options WHERE deleted=0 AND active=1 AND question=" . $val['id']);
$result = $query->result_array();
if ($query->num_rows() > 0) {
$count1 = 1;
foreach ($result as $res) {
if ($res['marks'] == 1) {
break;
} else {
$count1++;
}
}
}
// MAT answers options choose
$query1 = $this->db->query("SELECT * FROM mat_ans_options_choose WHERE deleted=0 AND active=1 AND uid=$uid AND q=" . $val['id']);
$result1 = $query1->result_array();
if ($query1->num_rows() > 0) {} else {
$data1 = [
'uid' => $uid,
'q' => $val['id'],
'option_chose' => $option,
'createdon' => $this->general_model->server_time(),
];
$this->db->insert('mat_ans_options_choose', $data1);
}
if ($count1 == $option) {
$marks = 1;
} else {
$marks = 0;
}
// if($marks==1 || $marks==0)
// {
// MAT answers
$query2 = $this->db->query("SELECT * FROM mat_answers WHERE deleted=0 AND active=1 AND uid=$uid AND q=" . $val['id'] . " AND type=" . $type . " AND sub_type=" . $val['sub_type'] . " AND level=" . $val['level']);
$result2 = $query2->result_array();
if ($query2->num_rows() > 0) {} else {
$data = [
'uid' => $uid,
'q' => $val['id'],
'type' => $type,
'level' => $val['level'],
'sub_type' => $val['sub_type'],
'mat_category' => $val['mat_category'],
'marks' => $marks,
'timeoutstatus' => $val['timeout'],
'createdon' => $this->general_model->server_time(),
];
$this->db->insert('mat_answers', $data);
}
// }
return 1;
} else {
return 0;
}

Answer 1

Use JS in which you disable the button after first click - it will work no matter if you are using AJAX or not.

Answer 2

You can use JS/jQuery to limit the number of requests made on the client side. For example by disabling the button on submit:
$("#my-button").prop("disabled", true);
But if the data is sensitive for duplicates (orders, user registration etc) you should make the request limit server side with PHP. You can achieve this by adding a unique index to the tables, either on user id or on a unique token that is submitted with the html form.

Answer 3

Create UNIQUE index in database for uid and q. The database will not insert same question's id from same user's id mulitple times.