0
我有一个分为多个表的论坛:分类,主题和主题。选择用户论坛活动,同时根据权限限制结果
CREATE TABLE forum_categories (
cat_id INTEGER UNSIGNED NOT NULL AUTO_INCREMENT,
role_id INTEGER UNSIGNED NOT NULL DEFAULT 0,
cat_name VARCHAR(50) NOT NULL,
PRIMARY KEY(cat_id),
FOREIGN KEY (role_id)
REFERENCES roles(role_id)
);
CREATE TABLE forum_topics (
topic_id INTEGER UNSIGNED NOT NULL AUTO_INCREMENT,
cat_id INTEGER UNSIGNED NOT NULL,
topic_name VARCHAR(50) NOT NULL,
topic_desc VARCHAR(100) NOT NULL,
PRIMARY KEY(topic_id),
FOREIGN KEY (cat_id)
REFERENCES forum_categories(cat_id)
);
CREATE TABLE forum_threads (
thread_id INTEGER UNSIGNED NOT NULL AUTO_INCREMENT,
parent_id INTEGER UNSIGNED NOT NULL DEFAULT 0,
topic_id INTEGER UNSIGNED NOT NULL,
user_id INTEGER UNSIGNED NOT NULL,
title VARCHAR(100) NOT NULL,
body TEXT NOT NULL,
create_date DATETIME NOT NULL,
PRIMARY KEY (thread_id),
FOREIGN KEY (parent_id)
REFERENCES forum_threads(thread_id),
FOREIGN KEY (topic_id)
REFERENCES forum_topics(topic_id),
FOREIGN KEY (user_id)
REFERENCES users(user_id)
);
类别表中有一个名为role_id
领域,如果将它设置为比0
以外的任何值,就是说只有该角色允许用户查看或与该类别中的主题进行互动。
我面临的问题是当试图拉特定用户最近的活动,让大家看到。我希望COUNT(*)
在包含请求的user_id
的线程表上,但我需要排除具有与受限制类别关联的topic_id的线程,除非请求该信息的用户具有权限。
如果查看特定线程,我只想提取topic_id
和检查是这样的:
// validate topic id and check for permission
$forum = new Forum();
$valid_topics = $forum->getTopics();
if (!array_key_exists($topic_id, $valid_topics)) {
// invalid topic id
}
$valid_categories = $forum->getCategories();
$role_id = $valid_categories[$valid_topics[$topic_id]['cat_id']]['role_id'];
if ($role_id == 0 || array_key_exists($role_id, $session_user_roles)) {
// user has permission
}
现在,我想我的PHP逻辑转换成SQL。这里是我后来的一个伪代码示例:
SELECT COUNT(*),
(SELECT role_id,
(SELECT cat_id
FROM forum_topics AS t2
WHERE topic_id = t1.topic_id) AS cat_id
FROM forum_categories
WHERE cat_id = t2.cat_id) AS role_id
FROM forum_threads AS t1
WHERE user_id = $user_id AND (role_id != 0 OR FIND_IN_SET(role_id, $session_user_roles) > 0)
请帮忙吗?