我在大多数查询中的表现非常糟糕。我在stackoverflow上阅读了很多,但仍有一些问题,也许有人可以帮助或给我一些提示?
基本上,我正在开发一个预订网站,其中包括以下表:
objects
+----+---------+--------+---------+------------+-------------+----------+----------+-------------+------------+-------+-------------+------+-----------+----------+-----+-----+
| id | user_id | status | type_id | privacy_id | location_id | address1 | address2 | object_name | short_name | price | currency_id | size | no_people | min_stay | lat | lng |
+----+---------+--------+---------+------------+-------------+----------+----------+-------------+------------+-------+-------------+------+-----------+----------+-----+-----+
MySQL中的OR:
CREATE TABLE IF NOT EXISTS `objects` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT 'object_id',
`user_id` int(11) unsigned DEFAULT NULL,
`status` tinyint(2) unsigned NOT NULL,
`type_id` tinyint(3) unsigned DEFAULT NULL COMMENT 'type of object, from object_type id',
`privacy_id` tinyint(11) unsigned NOT NULL COMMENT 'id from privacy',
`location_id` int(11) unsigned DEFAULT NULL,
`address1` varchar(50) COLLATE utf8_unicode_ci DEFAULT NULL,
`address2` varchar(50) COLLATE utf8_unicode_ci DEFAULT NULL,
`object_name` varchar(35) COLLATE utf8_unicode_ci DEFAULT NULL COMMENT 'given name by user',
`short_name` varchar(12) COLLATE utf8_unicode_ci DEFAULT NULL COMMENT 'short name, selected by user',
`price` int(6) unsigned DEFAULT NULL,
`currency_id` tinyint(3) unsigned DEFAULT NULL,
`size` int(4) unsigned DEFAULT NULL COMMENT 'size rounded and in m2',
`no_people` tinyint(3) unsigned DEFAULT NULL COMMENT 'number of people',
`min_stay` tinyint(2) unsigned DEFAULT NULL COMMENT '0=no min stay;else # nights',
`lat` varchar(32) COLLATE utf8_unicode_ci DEFAULT NULL,
`lng` varchar(32) COLLATE utf8_unicode_ci DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1451046 ;
预订
+----+------------+-----------+-----------+---------+--------+
| id | by_user_id | object_id | from_date | to_date | status |
+----+------------+-----------+-----------+---------+--------+
MySQL中的OR:
CREATE TABLE IF NOT EXISTS `reservations` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`by_user_id` int(11) NOT NULL COMMENT 'user_id of guest',
`object_id` int(11) NOT NULL COMMENT 'id of object',
`from_date` date NOT NULL COMMENT 'start date of reservation',
`to_date` date NOT NULL COMMENT 'end date of reservation',
`status` int(1) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=890729 ;
有几个问题:
1 - 除了主键,我没有设置任何其他关键字 - 我应该在哪里设置,应该设置哪个关键字?
2 - 我已经阅读了有关MyISAM与InnoDB的文章,我的结论是,在只读方面,MyISAM更快,而InnoDB则设计用于更频繁更新或插入数据的表。因此,当前对象使用MyISAM,预订使用InnoDB。混合使用这两种引擎是否明智?是否有更好的选择?
3 - 我需要查询在某个时间段内可用的对象(从from_date到end_date)。我已经阅读了(包括其他内容)stackoverflow上的这篇文章:MySQL select rows where date not between date
然而,当我使用建议的解决方案时,查询超时并且在返回任何结果之前非常缓慢:
SELECT DISTINCT o.id FROM objects o LEFT JOIN reservations r ON(r.object_id=o.id) WHERE
COALESCE('2012-04-05' NOT BETWEEN r.from_date AND r.to_date, TRUE)
AND COALESCE('2012-04-08' NOT BETWEEN r.from_date AND r.to_date, TRUE)
AND o.location_id=201
LIMIT 20
我错在哪里?如何最好地执行此查询?其他网站是如何处理的?我的数据库结构不适合还是只有查询有问题?我还有一些问题,但如果能得到任何帮助,我将非常感激!非常感谢您提前给出的任何提示或建议!