PHP を使用して製品在庫数カウントを実装するための手順とテクニック

CREATE TABLE `products` (
  `id` INT(11) NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(100) NOT NULL,
  `quantity` INT(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

<?php
  $host = "localhost"; //数据库主机
  $username = "root"; //数据库用户名
  $password = "123456"; //数据库密码
  $dbname = "inventory"; //数据库名称
  
  //创建连接
  $conn = new mysqli($host, $username, $password, $dbname);
  
  //检查连接是否成功
  if ($conn->connect_error) {
    die("数据库连接失败: " . $conn->connect_error);
  }
?>

<?php
  //查询商品列表
  $sql = "SELECT * FROM products";
  $result = $conn->query($sql);
  
  //检查是否有结果
  if ($result->num_rows > 0) {
    //输出数据
    while($row = $result->fetch_assoc()) {
      echo "ID: " . $row["id"]. " - 商品名称: " . $row["name"]. " - 库存数量: " . $row["quantity"]. "<br>";
    }
  } else {
    echo "暂无商品";
  }
  
  //关闭数据库连接
  $conn->close();
?>

<?php
  if ($_SERVER["REQUEST_METHOD"] == "POST") {
    //获取用户提交的商品ID
    $selectedProduct = $_POST["product"];
    
    //根据商品ID查询商品信息
    $sql = "SELECT * FROM products WHERE id = $selectedProduct";
    $result = $conn->query($sql);
    
    //检查是否有结果
    if ($result->num_rows > 0) {
      //输出商品信息
      while($row = $result->fetch_assoc()) {
        echo "商品名称: " . $row["name"]. " - 库存数量: " . $row["quantity"];
      }
    } else {
      echo "未找到商品";
    }
    
  }
?>

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
  请选择要盘点的商品：
  <select name="product">
    <?php
      //查询商品列表并生成选项
      $sql = "SELECT * FROM products";
      $result = $conn->query($sql);
      
      //检查是否有结果
      if ($result->num_rows > 0) {
        //生成选项
        while($row = $result->fetch_assoc()) {
          echo "<option value='" . $row["id"] . "'>" . $row["name"] . "</option>";
        }
      } else {
        echo "<option value=''>暂无商品</option>";
      }
    ?>
  </select>
  <input type="submit" value="提交">
</form>

<?php
  //关闭数据库连接
  $conn->close();
?>

<?php
  if ($_SERVER["REQUEST_METHOD"] == "POST") {
    //获取用户提交的商品ID和库存数量
    $selectedProduct = $_POST["product"];
    $newQuantity = $_POST["quantity"];
    
    //更新库存数量
    $sql = "UPDATE products SET quantity = $newQuantity WHERE id = $selectedProduct";
    
    if ($conn->query($sql) === TRUE) {
      echo "库存数量更新成功";
    } else {
      echo "库存数量更新失败: " . $conn->error;
    }
  }
?>

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
  商品名称：<span id="productName"></span><br>
  剩余库存数量：<span id="productQuantity"></span><br>
  新的库存数量：<input type="text" name="quantity"><br>
  <input type="hidden" name="product" id="productId">
  <input type="submit" value="更新">
</form>

<script>
  //根据选中的商品更新相应的数据
  function updateProduct() {
    var productSelect = document.getElementsByName("product")[0];
    var productNameSpan = document.getElementById("productName");
    var productQuantitySpan = document.getElementById("productQuantity");
    
    productNameSpan.innerHTML = productSelect.options[productSelect.selectedIndex].text;
    productQuantitySpan.innerHTML = productSelect.options[productSelect.selectedIndex].getAttribute("data-quantity");
    document.getElementById("productId").value = productSelect.value;
  }
  
  //页面加载完成后执行更新
  window.onload = updateProduct;
  //商品选择改变时执行更新
  document.getElementsByName("product")[0].onchange = updateProduct;
</script>

<?php
  //关闭数据库连接
  $conn->close();
?>