PHP 상품 재고 관리 시스템 구축 단계

CREATE TABLE `goods` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  `price` decimal(10,2) DEFAULT NULL,
  `stock` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "database_name";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

$sql = "SELECT * FROM goods";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "ID：" . $row["id"]. " - 商品名：" . $row["name"]. " - 价格：" . $row["price"]. " - 库存：" . $row["stock"]. "<br>";
    }
} else {
    echo "暂无商品";
}

if(isset($_POST["submit"])) {
    $name = $_POST["name"];
    $price = $_POST["price"];
    $stock = $_POST["stock"];
    
    $sql = "INSERT INTO goods (name, price, stock) VALUES ('$name', $price, $stock)";

    if ($conn->query($sql) === TRUE) {
        echo "商品添加成功";
    } else {
        echo "商品添加失败：" . $conn->error;
    }
}

<form method="post" action="">
    <label for="name">商品名：</label>
    <input type="text" name="name" id="name">
    <br>
    <label for="price">价格：</label>
    <input type="text" name="price" id="price">
    <br>
    <label for="stock">库存：</label>
    <input type="number" name="stock" id="stock">
    <br>
    <input type="submit" name="submit" value="添加商品">
</form>

if(isset($_POST["update"])) {
    $id = $_POST["id"];
    $stock = $_POST["stock"];
    
    $sql = "UPDATE goods SET stock = $stock WHERE id = $id";

    if ($conn->query($sql) === TRUE) {
        echo "库存更新成功";
    } else {
        echo "库存更新失败：" . $conn->error;
    }
}

<form method="post" action="">
    <label for="id">商品ID：</label>
    <input type="number" name="id" id="id">
    <br>
    <label for="stock">新库存：</label>
    <input type="number" name="stock" id="stock">
    <br>
    <input type="submit" name="update" value="更新库存">
</form>