How to update multiple rows in one table (mysql, php, pdo)

Question

the thing is when i left text area blank, i want it to delete that entry

I have a table in which i want to update primary key (RegNo) and (Name)

                              Table students
(Primary Key)                                            (Foreign Key)
 RegNo               Name              Passwd             ProjectID
 f12345              Ali                345                   1
 f12346             Chris               346                   1
 f12347             Ameer               347                   1

I am tried few ways,

$names = [
       ['reg'=> $_POST['s1_id'], 'name'=> $_POST['s1_name']],
       ['reg'=> $_POST['s2_id'], 'name'=> $_POST['s2_name']], 
       ['reg'=> $_POST['s3_id'], 'name'=> $_POST['s3_name']]
       ]; 

 $query="update students SET Name=:Name WHERE RegNo=:reg And 
 ProjectID='$id'";

 foreach ( $names as $name)
 {
   try
  {

    $stmt = $conn->prepare( $query );  
    $stmt->bindParam(':Name', $name['name']);
    $stmt->bindParam(':reg', $name['reg']);

    $result = $stmt->execute();
    $msg = "Record updated";

    //header("location:adminhome.php");
  }

  catch(PDOException $ex)
   {
      $msg = $ex -> getMessage();
   }
  } 

Through this way i was able to update Name column only. How i can update both RegNo and Name. I am new to back-end Programming. Don't know how to achieve this.

Answer 1

Something like this? I only added , RegNo=:reg this inside the SET because reg is already bound I think this is all you need to add.

I updated my answer because it will never match when you send an updated RegNo with your data structure. So you should send two RegNo, the old one, and the new one.

For deleting, I define two queries, one for delete and one for the update. Before we update the results I check inside the foreach if the new Students ID ( $name['reg_set'] ) is empty, if it is we run the $query_delete otherwise we will run $query_update

$names = [
       ['reg'=> $_POST['s1_id'], 'reg_set'=> $_POST['s1_id_set'], 'name'=> $_POST['s1_name']],
       ['reg'=> $_POST['s2_id'], 'reg_set'=> $_POST['s2_id_set'], 'name'=> $_POST['s2_name']],
       ['reg'=> $_POST['s3_id'], 'reg_set'=> $_POST['s3_id_set'], 'name'=> $_POST['s3_name']]
       ];

 $query_delete="DELETE FROM students  WHERE RegNo=:reg And ProjectID='$id'";

     $query_update="UPDATE students SET Name=:Name, RegNo=:reg_set WHERE RegNo=:reg And
     ProjectID='$id'";

 foreach ( $names as $name)
 {
   try
  {

            if(empty($name['reg_set'])){
                $stmt = $conn->prepare( $query_delete );
                $stmt->bindParam(':Name', $name['name']);
                $stmt->bindParam(':reg', $name['reg']);

                $result = $stmt->execute();
                $msg = "Record deleted";
            }else{
                $stmt = $conn->prepare( $query_update );
                $stmt->bindParam(':Name', $name['name']);
                $stmt->bindParam(':reg', $name['reg']);
                $stmt->bindParam(':reg_set', $name['reg_set']);


                $result = $stmt->execute();
                $msg = "Record updated";
            }


    //header("location:adminhome.php");
  }

  catch(PDOException $ex)
   {
      $msg = $ex -> getMessage();
   }
  }