ODBC PDO和Ajax的问题

I'm working on a project for work, and I've run into some issues. I'm creating dynamic elements based on PDO queries and ajax, and I've searched and searched to resolve my specific issue. Basically, I have two select boxes that are dynamically added from a database response, and regardless of which option is selected, all of the dynamically created buttons are made exactly the same. Selected Rack_G

I've also created timers for each Rack/Tray, and the same issue arises for the timers. There is only a record for Rack H Tray 8.Rack H Tray 8

My db_connect.php

$first = "odbc:TIMERODBC";
$user = "exampleuser";
$pass = "examplepass";
$pdo = new PDO($first,$user,$pass);
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

Below is my class.db.php file that queries my database

public function selectOven()
  {
    try{
      $stmt = $this->conn->query("SELECT sub.equipName FROM STR_EquipSubCategory sub LEFT JOIN STR_EquipCategory category ON category.categoryID = sub.categoryID GROUP BY sub.equipName");
      $data = $stmt->fetchAll();
      foreach($data as $row)
      {
        echo "<option value=" . $row['equipName'] . "><strong>" . $row["equipName"] . "</strong></option>";
      }
    }
    catch(PDOException $e) {
      return $e->getMessage();
    }
  }
  public function selectRack($oven) {
    try{

      $sth = $this->conn->prepare('SELECT storageBayName FROM STR_EquipSubCategory WHERE equipName =:oven');
      $sth->bindParam(':oven',$oven,PDO::PARAM_STR);
      $sth->execute();
      $data = $sth->fetchAll();
      echo "<select id='rack' class='custom-select mb-2'>Rack";
      echo "<option value ='Select Rack'></option>";
      foreach($data as $row)
      {
        echo "<option id=".$row['storageBayName']." value=". $row["storageBayName"] . ">". $row["storageBayName"] . "</option>";
      }
      echo "<select>";
    }
    catch(PDOException $e) {
      return $e->getMessage();
    }
  }

  public function selectRackTray($oven,$rack) {
    try{
      $sth = $this->conn->prepare("EXECUTE STR_GetTimerOpenTraysSp ?, ?");
      $sth->bindParam(1,$oven,PDO::PARAM_STR);
      $sth->bindParam(2,$rack,PDO::PARAM_STR);
      $sth->execute();
      $data = $sth->fetchAll();
      foreach($data as $row)
      {
        if(($row['material'] != 0) ) {
          echo "<div class='row'>";
          echo "<button type='button' id='tray".$row['storageBayName']." ". $row['sublevelID'] ."' class='btn btn-danger' data-toggle='popover'>Tray " .$row['sublevelID'] . "</button>";
          echo "</div>";
        }
        else {
          echo "<div class='row'>";
          echo "<button type='button' id='emptyTray".$row['storageBayName']. " ".$row['sublevelID'] ."' class='btn btn-success'>Tray " .$row['sublevelID'] . "</button>";
          echo "</div>"; 
        }
      }
    }
    catch(PDOException $e) {
      return $e->getMessage();
    }
  }

And now my ajax jQuery & Ajax

$(document).ready(function(){
  $("select#oven").change(function(){
    var selectedOven = $("#oven option:selected").val();
    $.ajax({
      type: "POST",
      url: "process-request.php",
      data: { oven : selectedOven }
    }).done(function(data){
      $("#rackResponse").html(data);
    });
  });
});
$(document).on('change', "select#rack", function() {
  var  selectedRack = ($(this).val());
  var selectedOven = ($("#oven option:selected").text());

  $.ajax({
      type: "POST",
      url: "process-a-request.php",
      data:
        { 
          rack: selectedRack,
          oven: selectedOven
        },
    }).done(function(data){
      $("#tResponse").html(data);
    });
});

If anyone can help me out, I would greatly appreciate it. Note, I'm not super experienced with PHP, but everything else seems to be working correctly.

My problem wasn't with ajax, php, or the PDO statements. I ran some tests on my stored procedure that I was calling, and found the problem there. Thanks for attempting to help me out.