在表单提交中向表格插入数据的最佳方法是什么？

Question

I have two tables wallet (table 1) and api (table 2).

Right now I have made the part where I insert the submitted data to my wallet table. This is the code for this specifically:

<?php
   include 'db.php'; 

   if ($_SERVER['REQUEST_METHOD'] == 'POST') {

      $coin = mysqli_real_escape_string($conn, $_REQUEST['coin']);
      $user_coins = mysqli_real_escape_string($conn, $_REQUEST['coins_quantity']);

      $sql = "INSERT INTO wallet (coin, user_coins) VALUES ('$coin', '$user_coins')";
      if ($conn->query($sql)){
          echo "Added successfully.";
      } else{
          echo "ERROR: Could not able to execute $sql. " . mysqli_error($conn);
      }

   }

?>

Where this is my form the code above:

<form method="post">
   <div class="form-group row justify-content-center">
      <label class="col-sm-3 col-form-label">Coin</label>
      <div class="col-sm-6">
         <select class="form-control" name="coin">
             <?php

             $sql = "SELECT name, symbol FROM api";
             $result = $conn->query($sql);

             while ($row = $result->fetch_assoc()) {
                 unset($symbol, $name);
                 $symbol = $row['symbol'];
                 $name = $row['name'];
                 echo '<option value="'.$symbol.'">'.$name.'</option>';
              }
             ?>
         </select>
      </div>
   </div>
   <div class="form-group row justify-content-center">
      <label class="col-sm-3 col-form-label">Coins</label>
      <div class="col-sm-6">
         <input type="number" class="form-control" name="coins_quantity" placeholder="5">
      </div>
   </div>
   <div class="form-group row justify-content-center text-center">
      <div class="col-sm-12">
         <button type="submit" class="btn btn-primary">Add</button>
      </div>
   </div>
</form>

In my table wallet (table 1) I have created columns which are coin, user_coins and coin_price.

While in table api (table 2) I have name, price, symbol and more.

I want to insert data to coin_price in wallet from the price column in the api table, and I want the price from the selected '<option value="'.$symbol.'">'.$name.'</option>';.

How can I do this?

Answer 1

I've found a way. You can:

1.) Put the coin id on the value of the select then,
2.) On your post method, find (where clause) the coin id and get the necessary data you want to insert them to another table.