如何使用PHP PDO通过数组元素方便地更新DB表中的3行？

I’m learning PHP and PDO. A bit confused with updating 3 rows in database by elements of array. I have an array of data $dateArray[$index], obtained by fetching from DB and calculating with another data. So finally, this array contains elements in such form:

var_dump($dateArray[$index]);

outputs

string(10) "2018-07-24" string(10) "2018-07-11" string(10) "2018-07-23"

A DB table looks like this: enter image description here

Now I need to write them to DB (UPDATE stored values) in 3 columns: day_remind1, day_remind2 and day_remind3 and then display in the HTML table.

I suppose I should:

  1. Make PDO prepared statement with UPDATE query;

  2. Organize loop of bindParam statements assigning elements of $dateArray[$index] to fields.

  3. Include execute in this loop to alternately update values of DB fields.

So this is how I do:

  $id = $_POST['id'];
  $day = $dateArray[$index];
  $sql = "UPDATE birthday_table SET day_remind1=:day, day_remind2=:day, day_remind3=:day WHERE id=:id";
  $stmt3 = $pdo->prepare($sql);

  foreach ($day as $dates=>$v) {
    $stmt3->bindParam(':day_remind1', $day);
    $stmt3->bindParam(':day_remind2', $day);
    $stmt3->bindParam(':day_remind3', $day);
    $stmt3->bindParam(':id', $id);
    $id = $v['id'];
    $stmt3->execute();
  }
  $db_handle = new DBController();
  // use AJAX variables column, editval, id containig user input 
  $result = $db_handle->executeUpdate("UPDATE birthday_table SET " . $_POST["column"] . " = '".$_POST["editval"]."' WHERE  id=".$_POST["id"]);

`

This doesn’t work, any data updated in DB, any error seen in console. Need clarification on how to fix my loop to solve my task.

You didn't bind the query params correctly.

when you do $stmt3->bindParam(':day_remind1', $day);, that means you are trying to inject the $day variable in a placeholder called :day_remind1.

But your 3 placeholders in your query are all named :day. Then you should edit your query to $sql = "UPDATE birthday_table SET day_remind1=:day_remind1, day_remind2=:day_remind2, day_remind3=:day_remind3 WHERE id=:id";

and remove the : when biding params:

$stmt3->bindParam('day_remind1', $day);
$stmt3->bindParam('day_remind2', $day);
$stmt3->bindParam('day_remind3', $day);
$stmt3->bindParam('id', $id);