How to update data without auto refresh, through PHP and Ajax functions?

I have the following functions:

if(!function_exists('returnGraficoData_Hora')){
  function returnGraficoData_Hora(){  
    include('conexao.php');
    $sql = "SELECT TIME(data_hora) AS data_hora FROM tbdados ORDER 
    BY id DESC LIMIT 4;";
    $stmt = $PDO->prepare($sql);
    $stmt->execute();
    $chartData_hora = [];

    while($linha = $stmt->fetch(PDO::FETCH_ASSOC)){
      $chartData_hora[] = "'".$linha['data_hora']."'";
    }
    echo join(",",array_reverse($chartData_hora));
  }
}

if(!function_exists('returnGraficoTemp')){
  function returnGraficoTemp(){  
    include('conexao.php');
    $sql = "SELECT Tlm35 FROM tbdados ORDER BY id DESC LIMIT 4;";
    $stmt = $PDO->prepare($sql);
    $stmt->execute();
    $chartTemp = [];

    while($linha = $stmt->fetch(PDO::FETCH_ASSOC)){
      $chartTemp[] = "'".$linha['Tlm35']."'";
    }
    echo join(",",array_reverse($chartTemp));
  }
}

if(!function_exists('tabelaDados')){
  function tabelaDados(){
    include('conexao.php');
    $sql = "SELECT * FROM tbdados ORDER BY id DESC LIMIT 15;";
    $stmt = $PDO->prepare($sql);
    $stmt->execute();

    while($linha = $stmt->fetch(PDO::FETCH_OBJ)){
      $timestamp = strtotime($linha->data_hora);
      $dataTabela = date('d/m/Y H:i:s', $timestamp);
      echo "<tr>";
      echo "<td id='data'>" . $dataTabela . "</td>";
      echo "<td>" . $linha->Ax . "</td>";
      echo "<td>" . $linha->Ay . "</td>";
      echo "<td>" . $linha->Ax . "</td>";
      echo "<td>" . $linha->Gx . "</td>";
      echo "<td>" . $linha->Gy . "</td>";
      echo "<td>" . $linha->Gz . "</td>";
      echo "</tr>";
    }
  }
}

Where the data appears:

<div class="table-responsive">
  <table class="table table-striped table-sm">
    <thead>
      <tr>
        <th>Data/Hora</th>
        <th>Ax</th>
        <th>Ay</th>
        <th>Az</th>
        <th>Gx</th>
        <th>Gy</th>
        <th>Gz</th>
      </tr>
    </thead>
    <tbody>
      <?php 
        include('../dao/leitura.php'); 
        tabelaDados();
      ?>
    </tbody>
  </table>
</div>

<script src="../js/Chart.bundle.min.js"></script>
<script src="../js/utils.js"></script>

<script>
var config = {
    type: 'line',
    data: {
      labels: [<?php 
        include('../dao/leitura.php'); 
        returnGraficoData_Hora();
      ?>],
      datasets: [{
        label: 'Temperatura',
        backgroundColor: window.chartColors.blue,
        borderColor: window.chartColors.blue,
        data: [<?php 
          include('../dao/leitura.php'); 
          returnGraficoTemp();
        ?>],
        fill: false,
      }]
    },
    options: {
      responsive: true,
      title: {
        display: false
      },
      scales: {
        yAxes: [{
          ticks: {
            min: 0,
            max: 50
          }
        }]
      }
    }
};

window.onload = function() {
    var ctx = document.getElementById('grafico').getContext('2d');
    window.myLine = new Chart(ctx, config);
};
</script>

I tested with Ajax:

    if(!function_exists('teste')){
      function teste(){
       include('conexao.php');
       $stmt = $PDO->prepare('SELECT Gx FROM tbdados ORDER BY RAND() 
       LIMIT 1');
       if ($stmt->execute()){
          $teste = $stmt->fetchObject();
          echo json_encode($teste);
       }
      }
    }

    if(isset($_POST['action']) && !empty($_POST['action'])) {
      $action = $_POST['action'];
      switch($action) {
      case 'test' : teste();break;
     }
    }

JS:

   function atualizar(){
    $.ajax({ url: '../dao/leitura.php',
     data: {action: 'test'},
     type: 'post',
     dataType: "json",
     success: function(teste) {
       $('#teste').html('<p>' + teste.Gx + '</p>');
     }
    });
   }

   setInterval("atualizar()", 100);
   $(function() {
     atualizar();
   });

Data is entering the bank every 7 seconds, I do not want real-time data, I just want to update the data without using the auto refresh and as new data is entered into the database. How do I do this using the functions I have there? Thank you.