PHP如何批量提交到数据库？

输入框条形好sn为多行换行数据(如下），目前只能单条数据插入到数据库，如何分割换行数据实现批量插入？
A123
B223
C001
输入框model为一个值"薯片"。最后数据库的数据为：
| ID | SN | MODEL |
| 1 | A123| 薯片 |
| 2 | B223| 薯片 |
| 3 | C001| 薯片 |

**
前端html：**
 <form class="layui-form" action="./actions/data_add.php" method="post">
                  <div class="layui-form-item">
                      <label for="phone" class="layui-form-label">
                          <span class="x-red">*</span>条型码</label>
                      <div class="layui-input-inline">
                          <textarea id="sn" name="sn" required="" lay-verify="required" autocomplete="off" class="layui-input" ></textarea>
                      </div>
                  </div>
 <div class="layui-form-item">
                      <label for="phone" class="layui-form-label">
                          <span class="x-red">*</span>机型</label>
                      <div class="layui-input-inline">
                          <select id="model" name="model" lay-filter="model" lay-search required="" lay-verify="required">
                          <option value="">请选择型号</option>
  </select>
                      </div>

                  <div class="layui-form-item">
                      <label for="L_repass" class="layui-form-label">
                      </label>
                      <button class="layui-btn" lay-submit lay-filter="add" onclick="func1();">提交 </button>
 <button type="reset" class="layui-btn layui-btn-primary">重置</button>
                  </div>
              </form>


**后端提交：data_add.php**
<?php
  require '../untils/functions.php';
  $sn = $_POST['sn'];
  $model = $_POST['model'];
  
  require '../untils/connect_db.php';
  $sql = "INSERT INTO products (sn, model,) VALUES ('$sn', '$model')";
  if ($conn->query($sql) === TRUE) {
      href('../add.php');
  }
  else {
      echo "Error: " . $sql . "<br>" . $conn->error;
  }
?> 

<?php
  require '../untils/functions.php';
  $sn = $_POST['sn'];
  $model = $_POST['model'];
  
  require '../untils/connect_db.php';
  $sn=explode(',',$sn);
  for($i=0;$i<count($sn);$i++){
      $sql = "INSERT INTO products (sn, model,) VALUES ('$sn[$i]', '$model')";
      if ($conn->query($sql) === TRUE) {
          href('../add.php');
      }
      else {
          echo "Error: " . $sql . "<br>" . $conn->error;
      }
  }
  
?>

代码大概是这个样子的

<?php
//只有提交时，下面的代码才会运行
if(count($_POST)){
    //正规表达式
    $arr = preg_split('/\r\n/',$_POST['text']);
    foreach ($arr as $key => $a) {
        echo $a;
        echo '<br/>';
    }
}
?>
<form action="" method="post">
    <textarea name="text"></textarea>
    <input type="submit" value="提交">
</form>

在PHP里面读到换行符进行第二行赋值