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php 实现分类

2026-02-28 14:54:49PHP

PHP 实现分类功能

数据库设计

创建分类表结构，通常包含id、name、parent_id等字段。示例SQL：

CREATE TABLE categories (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    parent_id INT DEFAULT NULL,
    FOREIGN KEY (parent_id) REFERENCES categories(id) ON DELETE CASCADE
);

递归查询分类

使用递归方法获取多级分类：

function getCategories($parentId = null) {
    $categories = [];
    $query = "SELECT * FROM categories WHERE parent_id " . ($parentId ? "= $parentId" : "IS NULL");
    $result = mysqli_query($connection, $query);

    while ($row = mysqli_fetch_assoc($result)) {
        $row['children'] = getCategories($row['id']);
        $categories[] = $row;
    }

    return $categories;
}

分类展示

前端循环显示分类：

php 实现分类

function displayCategories($categories, $level = 0) {
    foreach ($categories as $category) {
        echo str_repeat('&nbsp;', $level * 4) . $category['name'] . "<br>";
        if (!empty($category['children'])) {
            displayCategories($category['children'], $level + 1);
        }
    }
}

分类管理

添加分类的PHP处理代码：

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $name = $_POST['name'];
    $parentId = $_POST['parent_id'] ?: null;

    $stmt = $pdo->prepare("INSERT INTO categories (name, parent_id) VALUES (?, ?)");
    $stmt->execute([$name, $parentId]);

    header("Location: categories.php");
    exit;
}

无限级分类优化

对于大型分类系统，考虑使用闭包表或嵌套集模型提高查询效率。闭包表示例：

php 实现分类

CREATE TABLE category_path (
    ancestor INT NOT NULL,
    descendant INT NOT NULL,
    depth INT NOT NULL,
    PRIMARY KEY (ancestor, descendant),
    FOREIGN KEY (ancestor) REFERENCES categories(id),
    FOREIGN KEY (descendant) REFERENCES categories(id)
);

分类缓存

使用缓存减少数据库查询：

function getCachedCategories() {
    $cacheKey = 'all_categories';
    if (!$categories = apcu_fetch($cacheKey)) {
        $categories = getCategories();
        apcu_store($cacheKey, $categories, 3600);
    }
    return $categories;
}

分类验证

添加分类时的数据验证：

function validateCategory($name, $parentId) {
    $errors = [];

    if (empty($name)) {
        $errors[] = '分类名称不能为空';
    }

    if ($parentId) {
        $stmt = $pdo->prepare("SELECT id FROM categories WHERE id = ?");
        $stmt->execute([$parentId]);
        if (!$stmt->fetch()) {
            $errors[] = '父分类不存在';
        }
    }

    return $errors;
}

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