对页面进行排序时的数据库完整性问题

Question

I have almost finished building my cms with drag and drop page sorting and heirarchy editing.

Here is my pages table in my db.

CREATE TABLE `pages` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `metatitle` varchar(255) DEFAULT NULL,
 `metadesc` text,
 `metakw` varchar(255) DEFAULT NULL,
 `create_time` datetime DEFAULT NULL,
 `update_time` datetime DEFAULT NULL,
 `name` varchar(255) DEFAULT NULL,
 `url` varchar(255) DEFAULT NULL,
 `parent` int(11) DEFAULT NULL,
 `active` tinyint(1) DEFAULT NULL,
 `sort` int(11) DEFAULT NULL,
 `nofollow` tinyint(1) DEFAULT NULL,
 `deletable` tinyint(1) DEFAULT NULL,
 `navshow` tinyint(1) DEFAULT NULL,
 `type` enum('basic','dynamic','virtual') DEFAULT NULL COMMENT 'basic: only contains basic content\ndynamic: contains both dynamic and basic content\nvirtual: redirects to another page',
 `virtual_redirect` int(11) DEFAULT NULL,
 `route` varchar(255) DEFAULT NULL,
 `dynamic_desc` varchar(255) DEFAULT NULL,
 `content1` blob,
 `content2` blob,
 PRIMARY KEY (`id`),
 UNIQUE KEY `url_UNIQUE` (`url`),
 UNIQUE KEY `name_UNIQUE` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=19 DEFAULT CHARSET=latin1

As you can see from parent field, I'm using the adjacency list model for creating my page heirarchy.

Say I had this page structure...

|-Page 1
| |-Page 3
| |-Page 2
| |-Page 4
| |-Page 5
|-Page 6

If I moved page 3 up a level the structure would now look like this...

|-Page 1
| |-Page 2
| |-Page 4
| |-Page 5
|-Page 3
|-Page 6

Here's my problem.

The above example involves a fairly substantial number of query's ( for such a small tree). I have to change the sort numbers of pages 2-6 and the parent of page 3. That's 7 querys.

What i'm experiencing is that the moving operation produces different results each time I use it. ie: sometimes it works perfectly, other times the sort numbers don't update properly.

It's as though the database craps out on a few of the queries and pretty soon the consistency of the database is ruined.

I'm not sure whether it's because there are too many queries or some other factor. But I'm finding it very difficult to diagnose.

Any ideas what the problem might be?

Cheers Tom

Answer 1

我建议您阅读如何管理数据库中的分层数据