Error Number: 1064 in deleting data using Codeigniter 3 - php

Question

I want to deleting my data in the table, but i can't delete the data because of this problem. Error Number: 1064
This is my Controller
class Dosen extends CI_Controller
{
public function __construct()
{
parent ::__construct();
$this->load->library('form_validation');
$this->load->model('Dosen_model');
}
public function index()
{
$data['judul'] = 'Daftar Dosen';
$data['dosen'] = $this->Dosen_model->getAllDosen();
$this->load->view('templates/header', $data);
$this->load->view('dosen/index', $data);
$this->load->view('templates/footer');
}
public function tambah()
{
$data['judul'] = 'Form tambah data Dosen';
$this->form_validation->set_rules('nip','NIP','required');
$this->form_validation->set_rules('nama','Nama','required');
if ($this->form_validation->run()==FALSE)
{
$this->load->view('templates/header', $data);
$this->load->view('dosen/tambah');
$this->load->view('templates/footer');
}
else
{
$this->Dosen_model->tambahDataDosen();
$this->session->set_flashdata('flash','Ditambahkan');
redirect('Dosen');
}
}
public function hapus($nip)
{
$this->Dosen_model->hapusDataDosen($nip);
$this->session->set_flashdata('flash','Dihapus');
redirect('Dosen');
}
And this is my Model
<?php
class Dosen_model extends CI_Model
{
public function getAllDosen()
{
$query = $this->db->get('daftar_dosen');
return $query->result_array();
}
public function tambahDataDosen()
{
$data = [
"nip" => $this->input->post('nip'),
"nama" => $this->input->post('nama'),
"prodi" => $this->input->post('prodi'),
];
$this->db->insert('daftar_dosen',$data);
}
public function hapusDataDosen($nip)
{
$this->db->where('nip',$nip);
$this->db->delete('daftar_dosen',$data);
}
}
the output is :
A PHP Error was encountered
Severity: Notice
Message: Undefined variable: data
Filename: models/Dosen_model.php
Line Number: 23
Backtrace:
File: C:\xampp\htdocs\endtest\application\models\Dosen_model.php
Line: 23
Function: _error_handler
File: C:\xampp\htdocs\endtest\application\controllers\Dosen.php
Line: 40
Function: hapusDataDosen
File: C:\xampp\htdocs\endtest\index.php
Line: 315
Function: require_once
and then
A Database Error Occurred
Error Number: 1064
You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'IS NULL' at line 3
DELETE FROM daftar_dosen WHERE nip = '0001' AND IS NULL
Filename: C:/xampp/htdocs/endtest/system/database/DB_driver.php
Line Number: 691

Answer 1

The error message is very clear
Message: Undefined variable: data
In other words, somewhere there is a variable $data that is not defined.
Where in your code is $data found? The answer: In the function hapusDataDosen() in the call to $this->db->delete('daftar_dosen',$data);
It is hard to know exactly what you are trying to do. My guess is all you need to do is change
$this->db->delete('daftar_dosen', $data);
to
$this->db->delete('daftar_dosen');

Answer 2

Try this
public function hapusDataDosen($nip){
$this->db->where('nip',$nip);
$this->db->delete('daftar_dosen');
}
OR
public function hapusDataDosen($nip){
$this->db->delete('daftar_dosen', ['nip' => $nip]);
}
Don't use $data because
You are not passing it to model function
It is unnecessary to delete a record from DB

Answer 3

Try This --
In Model
public function hapusDataDosen($nip)
{
$this->db->where('nip',$nip);
$this->db->delete('daftar_dosen',$nip);
}

Answer 4

public function hapusDataDosen($nip){
$this->db->delete('daftar_dosen',array('nip'=>$nip));
}