关于差值参数$ _GET ['id']和$ id

Question

so i was writing code about deleting a post so i use this code

require_once 'core/init.php';

  if (isset($_GET['id'])) {
    if (hapus_data($_GET['id'])) {
      header('Location: index.php');
    }else {
      echo "gagal menghapus data";
    }
  }

and here is the delete function

function hapus_data($id){
    $query = "DELETE FROM blog WHERE id = $id";
    return run($query);
}`

so what i didnt understand is why this code work but the parameters is not the same as you can see i put hapus_data($_GET['id'] and then hapus_data($id) as the parameter of the function

Answer 1

The parameter sets, and assigns, the name of the variable in the function.

Since $_GET['id'] is a super global it would be the same as

function hapus_data() { 
     $id = $_GET['id'] 

but then you then couldn't later do

hapus_data(any_non_$_GET[id]_variable)

so doing it in the function definition is a better practice.

You should parameterize your query. This is SQL injectable. Something like,

function hapus_data($id){
    $query = "DELETE FROM blog WHERE id = ?";
    return run($query, array($id));
    // and then update `run` to bind the second parameter
}