2013-08-03 23 views
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?

回答

1

尝试这种方式

SELECT count(*) 
FROM forum_threads thr 
JOIN forum_topics top ON thr.topic_id = top.topis_id 
JOIN forum_categories fc ON top.cat_id = fc.cat_id 
WHERE thr.user_id = $user_id 
    AND fc.role_id IN (0,  24, 55, 888, .... list of user roles ...) 

在用户角色(最后一个条件)的列表中始终把0作为第一个数字,那么他的角色的其余部分。